and no new taxes, without voter approval. we have got to pull together not as republicans or as democrats but as californians first. at this stage in my life, i'm prepared to do exactly that. . captions paid for by nbc-universal television good evening. we start tonight with a major development of that terror threat involving explosive packages bound for the united states. officials in yemen are saying they have arrested a woman who arranged to ship the makeshift bombs which were disguised as computer printers. those parcels were destined to addresses in chicago, but thanks to a tip were intercepted by authorities overseas. tonight we are learning just how powerful those bombs were.

and despite some initial confusion among american intelligence officials, how serious a threat this has turned out to be. we have extensive coverage and want to begin with our justice correspondent pete williams. pete, good evening. >> reporter: lester, officials now say both packages that were intercepted overseas before they could get here contained laser printers the same model as this one. and inside both of them, the toner cartridges, the cartridges that normally hold the powdered toner were instead stuffed with a high explosive, a type that's a favorite of terrorists. all this officials say was artfully designed to avoid detection. these pictures taken by police in dubai tell the story, showing what was inside those printer cartridges, the high explosive known as petn. the same substance was in richard reid's shoe bomb and abdulmutallab is accused of concealing it in his underwear on that flight to detroit last christmas day. last january, "dateline" asked an explosive expert to

demonstrate the force of roughly petn in the underwear bomb. now u.s. officials say the toner cartridges held five times that amount of the same kind of explosive, potentially very powerful. in england where one of the packages was intercepted, authorities say it contained a working bomb. >> the target may have been an aircraft and had it detonated, the aircraft could have been brought down. >> reporter: officials say the bombs were also made with liquid detonators and cell phones acting as timers. investigators believe the terrorists may have actually been targeting passenger airplanes which some experts say carry roughly half the air cargo coming into the u.s. the packages were intercepted, officials say, because an intelligence source gave the u.s. their actual tracking numbers, allowing them to be located quickly. it was that information and not repeated screening that led to their discovery. still, the homeland security secretary says it's all part of the nation's defenses. >> we know we have to have a multilayered system. we know there's no screening

system that in and of itself is a silver bullet where terrorism is concerned. >> reporter: the package found in the uk came from yemen to cologne, germany, and the other went from yemen to quite ar and then to dubai and to the united arab emirates where it was stopped. both carried on cargo planes operating under less strict rules than passenger planes. for example, federal law does not require that all such cargo be screened. it's a fact whoever sent the packages from yemen may have chosen to exploit. >> this was clever, because of the way they hid the explosives in a toner cartridge. they put it in a cargo hold in a cargo plane. this was a way to bypass a lot of the security procedures the united states has put in place in recent years. >> reporter: in yemen the president said his country is determined to fight terrorism but warned against outsiders coming in to hunt down al qaeda. security was tight at shipping offices there where employees were questioned about the bomb shixts. tonight yemeni authorities say a woman and her mother have been arrested there based on a phone number on the cargo forms, but

u.s. officials have their eye on others they believe were involved and are optimistic more arrests are coming, lester. >> pete, do officials have a take right now on what the targets were? we know they were addressed to these places in chicago. were those the intended targets? >> reporter: there's a division here. their initial assumption based on what they're seen of this device is that the packages were designed to blow up in the air, but it's equally possible, some investigators say, that they were intended to get all the way to the two synagogues in chicago and be detonated there. i think the conclusion is going to depend on further analysis of the two explosive devices. >> pete williams tonight. pete, thank you. even before this incident, the rise of al qaeda in yemen has been a source of increasing concern among american intelligence officials. as our chief foreign correspondent richard engel now reports, it's a concern shared by yemen's overburdened government. >> reporter: the big problem with yemen is that it cannot control all of its territory. yemen is a traditional large

tribal society. what most people may not know is that yemen's government is pro-american. nbc news was taken by the government earlier this year to see its counterterrorism forces who are trained with american cooperation. yemen has often asked for more american help as it deals not only with active al qaeda cells but two domestic wars. in northern yemen, there's a conflict with shiite rebels. in the south, another with a group that wants to break away. in areas where the government has little or no control, al qaeda has set up an aggressive franchise. there was the attack on the "uss cole" off yemen in 2000. last christmas the plot to crash an airliner in detroit came from yemen. [ speaking in foreign language ] and then there's this man, anwar al awlaki, an american

living in yemen, who's believed to have inspired the shooter at fort hood. al qaeda even produces its first online english language magazine from yemen called "inspire." with articles like "how to make a bomb in the kitchen of your mom." the magazine calls on supporters to launch as many attacks as possible, arguing that even if they fail, they create publicity, disruption and economic loss. >> al qaeda at this point understands that it doesn't need to carry out successful terrorist attacks to have the impact that it's looking for. >> reporter: while there are al qaeda cells all over the world, lester, the u.s. officials are particularly concerned about the one in yemen, because of its clear desire to carry out an attack inside the united states. >> richard, i want to ask you, there was a u.p.s. 747 freighter that crashed in dubai about a month ago. it was presumed an accident, there was smoke reported in the cockpit. i think it killed both of the pilots. is anyone going back now and

thinking maybe there's some red flags that have been raised in that crash? >> reporter: yes. nbc news has learned -- this is a very interesting story. there was a crash in september, a cargo plane reported fire onboard, and the crew was killed. we were told that u.s. officials and emirate officials are going back, taking a harder look at that crash in the light of these attempted bombs that were sent to the united states, but that's so far no conclusions have been drawn. >> richard engel here in new york. thanks. while those explosive packages from yemen were being carried by cargo planes, commercial airline passengers tonight have new reason to wonder about what's being carried in the bellies of the planes they fly on. nbc's michelle franzen is at newark's international airport tonight with that part of the story. michelle? >> reporter: lester, passengers here at newark and abroad were met with strict additional security measures in light of the latest target involving cargo shipments. that's because more than half of

international air cargo bound for the u.s. is transported by passenger planes, not cargo jets. at airports around the world today heightened security following the cargo bombing attempts and heightened concerns for international travelers and those waiting for loved ones. >> with this situation going on, we have to be extra careful to be vigilant. >> reporter: at newark, jill gordon happily greeted her daughter becca, who arrived from london's heathrow. even though the suspicious packages filled with explosives were discovered on cargo jets, experts say those packages could have ended up on a passenger planes. nearly 60% of international cargo bound for the u.s. is transported on passenger flights. the problem -- screening regulations overseas vary from country to country. and that's what worries travelers. >> i don't know how well they screen those. that would be a concern to me. >> reporter: in contrast, here in the united states almost all cargo loaded on passenger planes

is physically screened, and the government is working to bring that to 100%. most is screened by the airlines and cargo shippers themselves. not the tsa. many travelers say they welcome additional measures to screen cargo and passengers. >> unfortunately, i think since what happened nine years ago, since then, we've gotten used to it and it won't go away. >> reporter: and one of the latest security measures rolled out here at newark a few days ago, and last week at jfk those full body image scanners. passengers can opt out of using them, but they are subject, then, to the new pat-downs by tsa agents. lester? >> michelle franzen in newark, thanks. this terror threat comes just three days before the midterm elections. on this final weekend of campaigning president obama is crisscrossing the country on a weekend blitz to hold on to key democratic seats in congress, and there are new developments in some of the key races on both sides of the country. we're live tonight with all of

it beginning with nbc's mike viqueira. he's traveling with the president in chicago. hello, mike. >> reporter: hello, lester. good evening. the president left washington this morning for one last weekend campaign swing. trying to close the deal with core democratic voters urging them to get to the polls and hold back what many expect will be a big republican wave. he began his day in philadelphia, at what amounted to a pep rally for campaign volunteers challenging the crowd to go out and knock on 20,000 doors between now and election day, boosting the chances of the senate democratic there in -- democrat there in pennsylvania who is locked in a tight battle with republican pat toomey. then it was on to connecticut, normally a solid blue state, but the president taking no chances. there to support another senate candidate dick blumenthal, and tonight here in his adoptive hometown of chicago, another big rally on another college campus, the university of chicago just a stone's throw from the house he still has here. lester, with experts now

predicting a republican blowout of democrats come tuesday, much of what the president is doing this weekend is damage control, trying to minimize losses in the house, although many say the house is already gone for democrats. and try to hold on to a majority in the senate. lester? >> mike viqueira in chicago. now to florida -- where earlier this week we learned that former president bill clinton leaned on the democratic candidate for senate kendrick meek to drop out of the race. now there are new reports of a bizarre offer to get meek to step aside. nbc's ron mott talked to mr. meek today, and he join us from wilton manors. ron? >> reporter: lester, good evening. they say three's a crowd. that's what we've got in the race for u.s. senate here in florida between the front-runner, republican marco rubio, governor charlie crist running as an independent and democratic candidate kendrick meek asked to drop out of this race. each time he answers absolutely not. today campaigning near fort lauderdale, meek said if anyone should drop out of this race it's governor charlie crist having already lost the republican party to the tea party backed candidate mark

marco rubio. meek said earlier this week about 5:00 a.m., governor crist left him a voicemail and later met with him and asked him to consider getting out of this race. he says he even offered him a christian cross while he mulled it over, and meek kept this to himself until word president bill clinton himself had even gone to meek to ask him to drop out of the race so democrats could throw support behind charlie crist and perhaps have the best chance at beating rubio. the president later came out and said that conversation didn't quite go that way and, in fact, the two of them have plans to campaign monday night in orlando. lester? >> ron, thanks from florida. now to nevada where the republican candidate for senate sharron angle has ramped up her unusual strategy of staying as far away from the media as possible. nbc's john yang joins us now from las vegas. john? >> reporter: lester, if there's any race of the referendum on the past two years it's this one. democrat harry reid, the most powerful man in the senate, a key player in the passage of

health care reform, republican sharron angle a tea party candidate, who wants to repeal health care reform. and this state has the nation's highest unemployment, home foreclosure, and bankruptcy rates. as you say this weekend, a new controversy involving sharron angle this weekend after two local television stations, including the nbc affiliate, surprised angle at the airport. the angle campaign told the stations they were no longer welcome to cover her election night party on tuesday night. they've since relented on one station and the other station is under review. on election day, voter turnout will be the key, and both sides are trying to energize their voters to get the voters to turn out on tuesday. last night angle had senator john mccain in, and on monday harry reid will have first lady michelle obama in. and one twist in this race, lester, in nevada, voters can vote for none of the above. so we'll have to see how that plays out. lester. >> john yang in las vegas. we appreciate it. a program note. tomorrow on "meet the press,"

the high stakes in this year's election. on tomorrow's program, two key party leaders, democrat tim kaine and republican haley barbour and also tomorrow john brennan, the deputy national security adviser who has been so visible during this latest terror threat. that's all coming up tomorrow morning here on nbc. when "nightly news" continues this saturday, the burning issue in california. the fight to legalize marijuana. and later, a massive crowd descends on washington for a day of stars and laughs, but was something more serious going on as well?

in california tonight, the battle over marijuana. in a state that's already legalized it for medicinal purposes there's now a measure on tuesday's ballot to legalize small amounts of pot for recreational purposes known as proposition 19. it's created quite a controversy. here's nbc's george lewis. >> reporter: to legalize pot -- or not. that's the question california voters will have to answer when they vote on proposition 19. those in favor include rock stars. >> so this is why i'm here. because i'm here as a mother and a cannabis user. >> reporter: those opposed include the obama administration's drug czar. >> the facts are that legalizing marijuana is something that the obama administration opposes, and the facts are it's not going to solve california's problem. >> reporter: proponents of proposition 19, including some labor unions, claim legalizing

marijuana would create new tax revenues for california, and up to 100,000 new jobs. >> the cannabis industry plans on doing that with the passage of prop 19 and the local totally supports those efforts. >> reporter: opponents warn of a big upsurge in marijuana abuse, and people driving under the influence of pot. >> i've never seen a legislative proposal or initiative proposal that's received such universal condemnation. >> reporter: but young people see it differently. >> i think legalizing marijuana would be a great thing. >> i'd say -- nine out of ten are going to vote yes. >> reporter: political organizers going after the youth vote are keeping a close eye on proposition 19. one theory is that the notion of legalizing pot will bring out young voters in great numbers. this man is co-president of the roosevelt institute. a student think tank at ucla. >> there's a lot of people who probably normally wouldn't be

avid voters who i think probably will get out to this election. >> reporter: in early polls, proposition 19 was ahead by a few percentage points, but a "los angeles times"/usc poll conducted last week shows the measure failing 51% to 39%. meanwhile, late-night comics get to poke fun at california once again. >> if prop 19 were a human, it would be the most popular candidate in california. >> reporter: so the question, come election day, how high are californians on legalizing pot? george lewis, nbc news, los angeles. up next, gathering storm. a new hurricane that could be very bad news for a place that is still struggling to get back on its feet.

there is a new threat churning out of the atlantic tonight. hurricane tomas. we have some video shot this morning in barbados when tomas was still a tropical storm, a very dangerous one. now it's very possible this storm could soon hard hit in haiti, a country still struggling after that massive earthquake. let's get the latest from the weather channel's todd santos. todd? >> reporter: good evening, lester. you mentioned it. certainly eyes on this system as it makes its way across lesser antilles. however, the fears we had going into this hurricane season, what would happen if something gets close to haiti? it looks like this one could at held come very close at very least. there's a look at it right now. a category 1 storm, 90 miles an hour basically 45 miles west-southwest of saint lucia, and that is at least one of the areas that's already had some of the issues with the flooding rain, power outages trees down and roof damage. this is the piece that really gets at least our attention. especially as you notice as this system continues towards the west and northwest it's going to be slowing down and even if it

just gets in the area just south of haiti even in that whole region, you run into some issues there with the flooding rainfall over tent cities, areas that have already had problems with deforestation. those are some of the bigger issues getting into the latter half of the week. the biggest message at this moment, that folks have four days to prepare for this system that could be a category 3 or better major hurricane by the time it gets to the central and north central caribbean sea. >> and i know you and your colleagues will be following it closely. todd santos, thank you. in colorado, hundreds forced to leave their homes near boulder to escape a dangerous wildfire being allowed back home tonight. calm air and high humidity helped keep the fire from spreading overnight. it's now described as 70% contained. when we come back, we've never seen a rally quite like this one. the one we saw today. what was it all about?

on the national mall today in washington, a big crowd turned out for an event that's a little hard to characterize. comedy show? well, yes. concert? yes. and also a pep rally of sorts. political rally? well, the organizers said, no. so what, then, was it? nbc's peter alexander has been there all day, and peter, we'll put it to you. what brought all of those folks out today? >> reporter: lester, it's a question we're still trying to wrap our heads around tonight. they came here clearly to see comedy central hosts jon stewart and stephen colbert. true to his word, onstage, stewart was not political. but in that giant crowd, from their banners to buttons, it's obvious that his fans viewed

this as something more than just entertainment. >> hello, and are you ready to restore sanity? >> reporter: for a day on the crowded national mall, jon stewart and stephen colbert were america's comedians in chief. >> as i look out here today, i can see we have over 10 million people. >> reporter: in fact, organizers estimate more than 200,000 people gathered for the satiric "rally to restore sanity and/or fear." >> bow before us, minions. kneel before czar. >> reporter: the event at times took the tone of a peace festival. ♪ with the former cat stevens in a musical duel with former rocker ozzy osbourne. ♪ two months after another huge crowd attended conservative commentator glenn beck's "rally to restore honor" stewart insisted this day was for

comedy, not politics. still, he clearly wielded significant political clout and many in the audience hopes it marks a turn away from bitterness towards tolerance. >> a real friend understands no matter what religious position someone plays we're all on the same team. >> is this a historic moment or entertainment? >> it is. >> insanity and a rational discourse back to politics. >> we live now in hard times. not end times. and we can have animus and not be enemies. >> reporter: during this divisionive political season stewart and colbert hope this can be remembered as a comedic call for calm. >> sanity will always be and has always been in the eye of the beholder. to see you here today has restored mine. >> reporter: and perhaps most striking of today's crowd was the fact there was a wide age range from students to senior citizens.

some said this was their woodstock. others, lester, said they were there for the first woodstock as well. >> all right. peter alexander in washington tonight. thanks. that's "nbc nightly news" for this saturday. i'm lester holt reporting from new york. i'll see you tomorrow morning on "today." then right back here tomorrow evening. good night. good evening, i'm diane devine. for the second time in less than six months the cow p