tonight on "nightline," mitt's moment. he's the man who wants to send barack obama packing. we're there with the candidate, mitt romney, delivers the biggest speech of his political life. state of emergency, on the gulf coast, entire towns underwater. homes destroyed by tornadoes, over a million without power. and today, frantic evacuations and rescues of families still trapped inside their homes. plus 100,000 balloons, tons of confetti. for a high stakes moment like this, the politicians call on one man. we go behind the scenes.

good evening, i'm terry moran at the republican national convention in tampa. this was mitt romney's big night. it was the night of his political life, no doubt about it. just a short while ago, he took center stage just behind me here and he gave this speech, the speech everyone had been waiting for, but voters across the country, tried to make the case why voters should fire barack obama and put him, mitt romney, in the white house. so the balloons have fallen. the music stopped, the crowd is dispersing, but what was said up there, will go a long way to defining mitt romney for voters and defining this campaign for the white house. ♪ >> reporter: it was the moment mitt romney had been working for for years. >> i accept your nomination for

president of the united states. [ applause ] >> reporter: all the miles traveled, all that money spent, all the campaigns and primaries filled with elusive hopes, scarred by bitter losses, and here he was, at last. >> i do so with humility, deeply moved by the trust you've placed in me. >> reporter: the delegates sat hushed. they and the country were waiting for some kind of answer, who is this man, so familiar, and yet still opaque this man who would be our president. >> here we stand. americans have a choice, a decision. to make that choice, you need to know where about me and where i'd lead our country. >> reporter: and to help to get to know romney more intimately, convention organizers rebuilt the stage, moving the podium down, literally bringing romney closer to the people. ♪ >> reporter: every moment

tonight was meant to be special, especially this one. clint eastwood, 82 years old, rambled a bit. but brought the crowd to his feet, nevertheless, with a call for change. >> when somebody does not do the job, we got to let them go. i'll start it, you finish it. go ahead -- >> make my day! >> reporter: that's the most popular theme here, obama's got to go. and romney went after it too. after disillusions obama voters. >> hope and change had a powerful appeal. but tonight i ask a simple question. if you felt that excitement when you voted for barack obama, shouldn't you feel that way now that he's president obama? >> but this was personal and emotional at times when he looked back at the days he and his wife ann were raising their five sons, days gone by. >> but if you ask ann and i what we'd give to break up just one

more fight between the boys, or wake up in the morning and discover a pile of kids asleep in our room -- >> reporter: it is a matter of trust, electing a president. >> good evening, fellow republicans. >> reporter: and that has been a theme here this week. you can trust mitt romney. the good son, who adored his successful father. the faithful husband who stood by his high school sweetheart for 43 years of marriage, through thick and thin, the doting dad of five and dilating grand dad of 18. >> you can trust mitt. >> reporter: ann romney who lives with m.s. and survived breast cancer with her husband's support, tested as only a wife can, tuesday night. >> he loves america. he will take us to a better place, just as he took me home safely from that dance. give him that chance. ♪ >> reporter: and last night, paul ryan spoke of romney as a

man of faith, a minority faith he's given so much of his life to as a bishop and major donor to the mormon church. >> the man who will accept jour nomination tomorrow is prayerful and faithful and honorable. he's a fine man. worthy of leading this optimistic and good-hearted country. >> reporter: but mitt romney's long public career, the way he's veered around on so many of the issues of the day, has raised questions about him, even here on the convention floor, as we heard the other day. >> what do you think mitt romney's biggest challenge is here at this convention? >> i think it's a matter of trust and, is he genuine in what he's saying? >> on health care. >> no, no, i like mandates. >> reporter: on abortion. >> i believe abortion should be safe and legal in this country. >> reporter: on ronald reagan's conservative legacy. >> i'm not trying to return to

reagan-bush. >> reporter: he's modified his positions in ways that have many left voters confused, even suspicious. what do the voters think of him? >> most don't know too much about it. that's number one. what voters want to know, how does that experience that he's had to date, how does it inform the policies he's going to propose as president of the united states? >> reporter: so one of romney's biggest task was to square the circle of his own political life. tonight he said his life experience means he can fix the problems the country faces, promising energy and nps, cutting the deficit and no new taxes for the middle class. in the end, what he promised was hard work and character. >> if i'm elected president of the united states, i will work with my energy and soul to restore that america, to lift our eyes to a better america, that future is out there,

waiting for us. our children deserve it, our nation depends on it, the peace and freedom of the world require it, and with your help, we will deliver it. let us begin that future for america tonight! >> and so the next chapter of mitt romney's life saga begins, did this work? we'll have to see. barack obama goes next week. just ahead, the crisis and aftermath of hurricane isaac, my co-anchor, bill weir is on the scene where thousands have had to evacuate their homes. [ thunder crashes ] [ male announcer ] if you think all batteries are the same... consider this: when the unexpected happens, there's one brand of battery more emergency workers trust in their maglites: duracell. one reason: duralock power preserve. it locks in power for up to 10 years in storage. guaranteed. so, whether it's 10 years' of life's sunny days... or... the occasional stormy one... trust goes a long way.

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throughout the week here at the republican national

convention, the specter of hurricane isaac has hovered over the proceedings. they flashed up the number on the big screen the number for the red cross for donations. bill weir is on the scene there in the aftermath down in new orleans. bill? >> reporter: well, wonder of wonders, we're getting a glimpse of the moon over new orleans tonight for the first time since the storm rolled in. and for the million people without power, they will take all the light they can get. i actually had an experience to be over this city today and met a couple who really exemplify isaac's aftershock. >> this is just to document what hurricane isaac is doing to our area. >> that is the voice of dottie daniels. and over there is the house of dottie and murray daniels. but that's not their white car. no, that was put there by the wind-churned lake ponchartrain. this afternoon, they loaded a suitcase and their 20-year-old

cat into the basket of a coast guard helicopter. and when they touched down, they were still shaking their heads at isaac's surprising power. >> the storm surge came up so fast that nobody expected anything like that. we've never seen anything like that in my time. >> reporter: that is coast guard lieutenant caitlin mitchell wurster. she and her crew have pent the last couple days plucking the wet and surprised out of isaac's aftermath. but she did have enough time to show me around the american water world that is southern louisiana today, and the trip was proof that zip code affluence doesn't matter to mother nature. i saw mansions in slidell and shacks in plaquemines parish, sharing equal misery. isaac left such a mess out here. the daniels live in la place which is a complete disaster zone, the site of so much human

drama today. matt gutman has the latest details. >> reporter: communities in exodus, faces of desperation, young, old, frightens faces, yet relieved for the rescuesers to arrive. tens of thousands on the move as the awares rise faster than they could flee. in la place, thousands of national gardsmen and volunteers looking like an amphibious assault. this deer barely keeping fist head above water. in mississippi, a tornado crushing this house. my crew and i spent the day in la place, louisiana, where 3,100 residents were evacuated by helicopter and boat. we set out in the dead of night to link up with alpha team of the louisiana wildlife and fisheries. >> driving through three feet of

water. this place is nearly impassable. all the roads in and out, except for one, apparently, are out. >> reporter: finally at dawn, we found dwaine parker. with ten shallow boats we rowed towards developments entirely submerged. >> is it going down? >> on the rise just a tad. >> even the rescuers were shocked. >> we went through katrina, but never had the flooding. never had this before, never, never. >> reporter: while the fortress of levees kept the city safe, some of the smaller surrounding communities were swamped as their own local levees failed to protect them. the water, relentless. this woman, wading through in search of her father. >> he's right here on the corner. >> he stayed thinking this would be safe and wouldn't flood. >> yeah, it doesn't flood for

katrina. >> most homes had been abandoned. >> anyone there? >> reporter: the water rising four inches an hour, now lapping over street signs, the tops of mailboxes and cars, barely poking out of the water. while most of her neighbors had been ferried to safety, anna mcclung stayed. >> the house is ruined. everything's ruined. it's okay because we're out. now we just have to get to my husband to let him know we're okay. it was stupid for me to wait this long. i'm very glad that i have family and friends to help. >> reporter: now she was still trying to salvage some of her belongings. she and her family boarded our boat and we ferried her to safety. so many carried only the clothes they were wearing and pets. amidst the cold and damp and the loss -- >> i lost everything pch. >> it was scary. >> this is the worst it's ever been. i've never seen it like that.

>> reporter: while to the north of new orleans, a new anxiety today, tens of thousands more people told to evacuate when a dam threatened to break. >> sometimes the keepsakes are more important than the furnitu furniture. >> reporter: we were there as families were given 90 minutes to flee. what are you taking? >> pictures of my siblings, my children, my sister's children. >> reporter: how stressful is this? you have very little time. >> very, very stressful. >> reporter: the worry, this lake would spill over, and tonight engineers are using pumps to relieve the pressure on the swollen dam. we were lucky to get out of there. the back road we took to get in was more flooded on the way out. we spoke with rescuers who have gone back in, they say everybody who wanted to be evacuated has been. still the national guard will go back in using thermal technology

to make sure nobody was left behind in an evacuation area. >> matt, many thanks. so much work to do, so many stories to tell. abc's extreme weather team will keep doing just that tomorrow morning on "good morning america." let's go back to tampa and terry. >> bill, you and i are in different worlds tonight. thank you for your work and matt for his work down there as well. here at the convention, the show went on, including everybody's favorite moment, the balloon drop. when we come back, the man behind the magic of that big drop.

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it's a tradition everybody loves at these conventions, the big balloon drop. abc's david wright meets the man whose military precision and years of experience are behind the big balloon drop. >> reporter: it's the crowning moment for every candidate, if for the nation's highest honors, the money shot, anointing the crowd in red, white, and blue. pulling it off and this man's responsibility. he's uniquely qualified. >> my first jop in life was as a balloon seller in disneyland. >> reporter: skills he's honed

in 40-plus years as a balloon man. >> i can do a thousand balloons an hour by myself. >> you're great at birthday parties. >> reporter: birthday parties, and gop conventions. do you do democratic conventions? >> we did the one in l.a. back in 2000. >> reporter: in 1980, they seemed to come down one by one. >> supposed to be a big huge drop, the end of the convention, a great hoorah and we all said it was an omen, and it turned out to be. >> in 2004, cnn was listening to the audio during john kerry's balloon drop. >> all balloons should be moving. drop it. >> bursting his bubble on what was supposed to be a big night.

the republicans are good at this stuff. in 2004, he dropped a record 100,000 balloons. four years later, double that number. so many balloons, nbc's andrea mitchell, seemed to be drowning. >> she was in a spot where they were loading up on her. they'll be some spot tonight that gets an overwhelming amount of balloons. >> reporter: tonight they were hoping to avoid the avalanche. so they scaled back, 120,000 or so. it was picture perfect. a toast in red, white, and blue. i'm david wright for "nightline" in tampa. >> thanks to david wright for that cracker jack reporting on the balloon drop. thanks for watching abc news. "good morning america" will have the latest on the storm. i'll be in charlotte next week at the democratic national convention. jimmy kimmel and up next and we'll see you he