on our broadcast tonight, the day after the democrats fire up their convention with their sales pitch for another term, the reality sets in and the new jobs numbers are out. also, our truth squad goes over some of what we heard in charlotte. would you want to know? detecting alzheimer's decades before the first symptoms. it may now be possible. out of the park. summertime visitors to one of our more iconic national parks may be carriers of a fatal disease and not yet know it. and breaking his silence. clint west eastwood goes public, reveals the real story behind that convention speech that people are still talking about. "nightly news" begins now. >> from nbc news world headquarters in new york, this is "nbc nightly news" with brian williams. >> good evening. propelled by thunderous applause coming out of charlotte, where we last saw you just last night,

president obama, after launching his reelection effort, was hit head-on by the economic reality today even though 96,000 jobs were added to the u.s. economy in the month of august, and even though the unemployment rate fell from 8.3 to 8.1%, both the need and expectations were greater than that. and so with economists using words like "anemic," that affected what the campaign was hoping would feel much more like a post-charlotte victory lap. the economy remains the big issue in this campaign. and we begin our coverage of all of all of it tonight with white house correspondent kristen welker traveling with the president in iowa city tonight. kristen, good evening. >> reporter: good evening to you, brian. well, president obama left charlotte this morning with the vice president and first lady to hit pivotal swing states, and he tried to cast that jobs report in a positive light. campaigning in new hampshire, mr. obama took the long view on

jobs. >> today we learned that after losing around 800,000 jobs a month when i took office, business once again added jobs for the 30th month in a row. we know it's not good enough. >> reporter: behind the scenes, white house officials and campaign operatives echoed senior white house adviser david plouffe who told supporters we come out of the convention with momentum. but the jobs report threatens to slow that momentum only hours after the president addressed the democratic national convention, what most were describing as a successful week. >> know this, america, our problems can be solved. our challenges can be met. the path we offer may be harder, but it leads to a better place. and i'm asking you to choose that future. >> reporter: instead of the rousing rhetoric the president had employed before an outdoor crowd of thousands in 2008, last night mr. obama struck a more professorial tone in a gathering that had been forced inside by bad weather. >> you didn't elect me to tell you what you wanted to hear, you

elected me to tell you the truth. >> reporter: today the president ridiculed the republicans. >> tax cuts when times are good, tax cuts when times are bad. tax cuts to help you lose a few extra pounds. >> reporter: last night, the vice president threw the sharpest barbs. >> the most fascinating thing i found last week is when governor romney said that as president, he would take a jobs tour. well, with his support for outsourcing, it's going to have to be a foreign trip. >> reporter: the president campaigns next in the battle ground state of florida where the unemployment rate is higher than the national average. kristen welker, nbc news, iowa city, iowa. this is peter alexander in nashua, new hampshire. reenergized and confident, mitt romney storms back on to the campaign trail in iowa today, looking to capitalize on the weak jobs numbers that he criticized as disappointing and disheartening. >> it's been 43 straight months

above 8%. there are today 23 million americans that are out of work or stopped looking for work or are underemployed. it's a national tragedy. >> reporter: if last night was the party, romney said, this morning was the hangover. and while romney says he didn't watch the president's speech, today he blasted his opponent for failing to do what he said he would. >> as a matter of fact, i can think of very few of the promises that he made four years ago that he has kept. >> reporter: romney's surrogates weighed in as well. >> how about it,? >> this is not what president obama promised. i would argue this is the result of failed leadership in washington, bad fiscal policy coming from the administration. >> i should tell you that i feel right at home. >> reporter: ann romney targeting women in the battleground state of virginia. >> more women are unemployed now than men. more women are wondering every day how are they going to make the bills and all those payments they've got piling up.

>> reporter: and to launch its two-month sprint to election day, the romney campaign is airing more than a dozen new ads. >> we're not better off under president obama. >> reporter: in eight key swing states, all of which the president won in 2008. notably absent, michigan, pennsylvania, and paul ryan's home of wisconsin. but the campaign insists it still considers those states to be winnable. and i spoke to a top romney adviser late this afternoon and asked if that weak jobs number would be something they focus on over the next several days. that adviser said it would be a focus for the campaign, brian, over the next 60 days. another significant focus going forward preparing for next month's critical debate. the campaign knows that will be their next chance to speak to a major audience. >> peter alexander on the trail and kristen welker before that. thanks to you both for starting us off tonight. and we have more on these job numbers out today. david faber has come by to join us from cnbc headquarters. david, explain what people are asking their tv sets. how is it bad news that there was a net gain of 96,000 jobs,

that the unemployment rate went down? >> you know, the number of people actually participating in the labor force also went down. people gave up. i said you know what? i'm not even going to look for work anymore. they no longer count in that overall pool. hence the people amongst that pool who are not working actually fell as a percentage, from 8.3% to 8.1%. a good headline for democrats, but that's all it is. in fact, the 96,000 jobs that were added, brian, was not what economists certainly were expecting. 125,000 was kind of the reigning number, and not what many had hoped for as well. >> so just two more of these reports before people go to the polls. >> that's right. we have two more employment reports. of course, when you look deeper within this report itself also, you have to remember the creation of certain jobs not what people might hope for. services were up 119,000. but that's a lot of restaurant workers and the like, not high-paying jobs. manufacturing, which did have something of a rebound during the course of this year down

15,000, while construction, of course, as you see right there in terms of housing and the like, we're hoping for a rebound. that was flat. >> all right, david faber, as always, thanks for stopping by to help explain all this. >> my pleasure. this comes, of course, following a convention where we heard democrats say over and over "we're on the fix, we're on the mend, we need more time." as was the case with the gop in tampa, not everything that was said from the podium checked out when compared with the facts. we get our fact check tonight from our chief white house correspondent chuck todd. >> reporter: well, the president generally stuck to the facts last night. he did use a little budgetary slight of hand. >> i will use the money we're no longer spending on war to pay down our debt and put more people back to work. >> reporter: that so-called peace dividend doesn't exist. the wars in iraq and afghanistan were paid by borrowing and increasing the national debt. stopping the war doesn't free up any new money. this claim about obama's jobs record raised questions.

>> here is another job score. president obama, plus 4.5 million. congressional republicans, zero. >> reporter: it's true since january 2010 the economy has gained over 4.5 million private sector jobs. but mr. obama had already been president for a year by then when the economy was hemorrhaging jobs. if you begin counting when he took office, it's a net gain of about 415,000 jobs. vice president joe biden actually got that right last night by including the time span. >> we have since created 4.5 million private sector jobs in the past 29 months. >> reporter: but biden went out on a limb with this charge. >> they're not prepared to do anything about the debt if it contained even $1, i'm not exaggerating, even $1 or one cent in new taxes for millionaires. >> reporter: in fact, several

republican plans, from speaker john boehner to pennsylvania senator pat toomey included tax increases for wealthy americans. but bipartisan negotiations breck down over how much those increases should be. >> republicans will end the medicare guarantee. >> another frequent and misleading charge. >> so instead of the medicare guarantee, republicans would give seniors a voucher. >> reporter: while republicans want to restructure medicare, their latest plan does not end the guarantee. in fact, in the most recent version of paul ryan's budget plan, endorsed by mitt romney, traditional medicare would be an option for future seniors. with 60 days to go, neither campaign seems ready to back down from any of these charges, in spite of the facts. chuck todd, nbc news, washington. >> and we wanted to let you know, mitt romney will be the exclusive guest on "meet the press" with david gregory this weekend, his first appearance on the broadcast during this election cycle. that's sunday morning on this nbc station. federal officials have now expanded a worldwide alert to all those who have vacationed at

yosemite national park this summer due to an outbreak of the deadly hantavirus, an illness spread to people by mice. and now 29,000 summertime visitors are being warned about the risk of illness. our report tonight from nbc's janet shamlian. >> reporter: a ticket to splendor of yosemite national park now comes with a warning. >> and there is information about the hantavirus in here. >> reporter: amid the vast granite cliffs and breathtaking waterfalls, the deadly hantavirus is also here. eight confirmed cases in the park. three people have died. because yosemite draws so many tourists from outside the u.s., the world health organization issued a global alert about the rare rodent-borne virus. >> someone told us do you know there is a virus in yosemite park. we say oh, yes, we're going to there in a couple of days. >> reporter: the popular curry village has been the epicenter of the outbreak. rangers believe mice got into the inner walls of some of the area's tent cabins.

until now, all the cases have been tied to a single location here on the valley floor. now with a confirmed case in a different part of the park, there is concern the danger zone could be much wider. health officials say as many as 29,000 people who visited the park could be at risk, almost triple their assessment of 10,000 just days ago. >> the letter and e-mail that we're sending them is a health alert saying that we have had these cases, there is no need for, you know, immediate action unless people are exhibiting symptoms. >> reporter: the early symptoms of hantavirus mimic the flu -- headaches, fever, and body ache. but the deadly virus cannot be transmitted from one person to another. >> of course i'm concerned. i don't want to get a virus that's going to kill you. >> reporter: he didn't cancel his trip, but others have. hard to get reservations made a year in advance have become no-shows as caution canceled many vacations. janet shamlian, nbc news, yosemite national park. still ahead, as we continue

along the way on a friday night, an alzheimer's warning years before symptoms show up. what researchers are learning, and what it could mean for early treatment. and later, why a ball boy is getting a lot of attention at this year's u.s. open.

now to that tough question, would you want to know decades in advance if you were going to join the over five million americans living with alzheimer's disease? a new medical discovery tells us changes in the brain happen way before the symptoms are felt. that could mean people at risk could be identified long before they start to have any memory loss, and that raises all kinds of tough questions. our story tonight from our chief science correspondent robert bazell. >> reporter: some members of the heinrichs family from davenport, iowa, carry a terrible genetic mutation. >> that's grandma. >> reporter: if they have it, they will definitely develop alzheimer's disease, usually before age 50. for now they have decided not to

know who carries the gene. >> we decided we didn't want to know. and i think we decided as a collective group that we all felt about the same. >> reporter: by studying 128 members of such families who carry the rare mutation, researchers have discovered a disturbing new aspect of alzheimer's. >> brain changes that ultimately result in alzheimer's dementia occur 15 to 20 years before there are any signs of symptoms of dementia. >> reporter: what happens is a buildup of a protein called beta amyloid measured in spinal fluid or with brain scans, which many scientists believe is the prime cause of alzheimer's. alzheimer's researchers say the drugs to treat or prevent the disease may have to be given years or even decades before symptoms develop. to try to find those drugs, they'll be testing more and more younger and younger people who could be at risk for the disease far in the future. several companies are working on drugs to lower beta amyloid. >> the wasting of the brain.

>> reporter: if they are successful, some doctors believe that alzheimer's testing will become as routine as testing cholesterol for heart disease. >> if one of the tests that begin to be performed perhaps at age 40 on an annual or biannual basis to determine who is at the highest risk for alzheimer's disease. >> reporter: but until those drugs are available, doctors predict that most people like the heinrichs family will choose not to know whether they are at risk. >> by not knowing, i'm willing, you know, to play the odds that eventually they're going to find a cure for it. >> reporter: robert bazell, nbc news, new york. when we come back here tonight, clint eastwood breaks his silence about that speech. specifically, did the republicans at the convention know he was going to do that?

here is something you don't see every day. the three u.s. senators sometimes called the three amigos, john mccain, joe

lieberman, lindsey graham, crushing wine grapes in the former soviet georgia made for some very interesting pictures on the web. and perhaps after realizing how this looked, sator mccain's office put out a very sober press release late today about the serious business of the trip, including a meeting with president shalikashvili, whose office took the video down from the web. no mention in the press release of the dance of the wine makers. clint eastwood spoke out for the first time since the speech at the gop convention last week. those who watched felt as if he was making something up on the fly. it turns out that's pretty much what happened. our report tonight from nbc's andrea mitchell. >> reporter: a week later at the democratic convention, clint eastwood's chair was still getting laughs. >> i know it's an iffy chair. it makes you nervous, doesn't it. that's all right. i'm going to sit on it. >> what do you mean shut up? >> reporter: it was a rambling, unscripted appearance at the republican convention that went more than twice as long as it was supposed to. it went viral.

eastwood immediately started trending on twitter. mitt romney's top aides acknowledged they didn't know what eastwood would say, unheard of at a national political convention, where speakers are timed to the second. >> i know what you're thinking. >> reporter: now eastwood has told his hometown newspaper "the carmel pinecone" they vet most of the people, but i told them you can't do that with me because i don't know what i'm going to say. he said the idea of interviewing an imaginary president obama in an empty chair came at the last moment when a stagehand kept asking him if he wanted to sit down. inspiration struck as he was walking out on stage, telling the paper, "when i saw the stool sitting there, it gave me the idea. i'll just put the stool out there, and i'll talk to mr. obama, and ask him why he didn't he keep all of the promises he made to everybody." >> so mr. president, how do you handle -- how do you handle promises that you have made? >> reporter: a peer survey cited eastwood's speech as the republican convention's top

highlight, beating out mitt romney's speech. now like eastwood's movies, his empty chair has found its place in pop culture. andrea mitchell, nbc news, washington. a new movie for kids has just set the record for the worst box office opening in cinematic history. "the oogieloves and the big balloon adventure" made $448,000 over the labor day weekend. while that's a lot of money, it's not as much as movies cost to make. it comes out to $207 per screen. that means a few families per theater, maybe even some empty movie shows. this adventure in cinema stars chazz palminteri, cloris leachman, toni braxton. among others. it is the brainchild of the teletubbies creator. this may explain why he was blowing off a little steam in las vegas recently. the british military let it be known today that prince harry has been deployed to afghanistan this time, where he is flying helicopter missions.

in the military, by the way, he is addressed simply as captain wales. up next here tonight, a young man's extraordinary journey from the battlefield to the baseline.

the u.s. open tennis

tournament wraps up this weekend here in new york. and if you look closely, you may notice something different about just one of the 249 people who scurry across the court, retrieving the tennis balls. ryan mcintosh is a veteran of the war in afghanistan, and now he has taken this high-profile job to make a point. his story tonight from nbc's jenna wolfe. >> reporter: for two weeks every summer, new york city is the center of the tennis universe. the best players in the game in one of the biggest tournaments, the u.s. open. but this year it's one of the newest faces on court drawing attention. so new, in fact, before this tournament, he had never really been on a court at all. >> always growing up i would play football. and, you know, that was the highlight of my life. >> reporter: ryan mcintosh always wanted to serve his country. so he enlisted during college and was soon deployed to afghanistan. but one afternoon on patrol changed his life forever. >> i woke up about ten feet in the air, you know, with dust all

in the air, and my ears were ringing. >> reporter: just 100 yards from his base. >> i realized that my toes were gone. >> reporter: a land mine had blown off his right leg. do you remember the phone call to your wife after you woke up? >> yeah, that's terrible. that was the worst phone call i ever had to make, i lost my leg. that was hard because i had to be strong for her but at the same time strong for myself to realize those words were really coming out of my mouth. >> reporter: ryan was also a soon to-be father, and the thought of not being there for his son was overwhelming. >> i always had my dad, and that was my biggest anchor point was my dad. when my son was going to grow up, i wanted me to be his biggest anchor point. >> reporter: staying anchored, but wanting to keep moving, ryan found out about the chance to work the u.s. open through a wounded warriors program, and his heart hasn't gone unnoticed. >> if that's not inspiration, forget the tennis players, but for guys in life. some of the guys that play tennis had that kind of heart, we'd see some more good matches,

wouldn't we? >> to hear ryan's story, you know, anybody who went through that and came out a better person on the other end, you know, those are the heroes that we should be reading more about. >> reporter: as for his future -- >> i've just had so much fun with my life so far. and i hope it's everything that i want it to be and more. >> reporter: a young man making the most of his second chance. jenna wolfe, nbc news, new york. >> and that is our broadcast for this friday night and for this week, back home in new york. thank you for being here with us. i'm brian williams. we, of course, hope to see you right back here on monday. in the meantime, have a good weekend. good night. -- captions by vitac -- www.vitac.com