With a close win in Ohio and other victories in Virginia, Massachusetts, Vermont, and Idaho, he remains at the front of the pack.
1:06 a.m. That's all, folks. With only Alaska left to report, we're signing off for the night. Read Molly Ball's analysis of all tonight's results here: A Super Tuesday Nailbiter Puts Romney on His Heels.
Check back in the morning for more analysis from The Atlantic's politics team. --DG
12:44 a.m. Joe the Plumber wins.
COLUMBUS, Ohio (AP) - Ohio's 'Joe the Plumber' of 2008 campaign fame wins GOP nomination in US House race #2012— Phil Elliott (@Philip_Elliott) March 7, 2012
He'll face Democratic Rep. Marcy Kaptur in the general election. --DG
12:31 a.m. Romney wins Ohio. Well, there it is, folks: NBC and the Associated Press have both declared Mitt Romney the winner of the Ohio primary. It's the culmination of a stomach-churning evening: early exit polls showed Romney polling strongly, but as the actual votes came in Santorum gained a significant lead, only to see it melt away as votes from the Cleveland and Columbus metropolitan areas -- which tend to be more socially liberal, better educated, and wealthier -- came in to give Romney a victory. It's unquestionably good news for Romney, who proved he can win in the Rust Belt, and bad news for Santorum, who was unable to hold on to a lead in a state very similar to his own Pennsylvania. A win would have given him serious momentum to keep challenging Romney, though he's vowing to stay on. Still the news could have been much better for Romney, he's escaped with his life, but will have face continued doubts over his inability to finish his rivals -- even though his delegate total by the end of the night puts him well on the way to winning the Republican nomination. Even with the close margin of victory, the former Massachusetts governor will take home the lion's share of the Buckeye State's delegates. --DG
12:05 a.m. Meanwhile, elsewhere in Ohio... In addition to the presidential race, there are actually two notable House races, and both threaten to end the careers of divisive, partisan members, one on each side of the aisle. In the first, Rep. Jean Schmidt appears to have lost to fellow Republican Brad Wenstrup, an Iraq war veteran, in an upset. Schmidt aroused controversy by calling decorated Marine veteran and fellow member of Congress John Murtha a "coward" and appearing to endorse the views of a birther attendee at an event.
But the bigger story is in the Ninth District, where Rep. Marcy Kaptur is poised to defeat Rep. Dennis Kucinich. It's a hard fall for Kucinich, who just four years ago ran for the Democratic nomination for president. But the two veteran Democrats found themselves pressed into a single district when House maps were redrawn, with the Republicans who control the state government seeing a chance to get rid of one of them. The new district included parts of Cuyahoga County -- Kucinich's stronghold since his days as "Boy Mayor" of Cleveland in the 1970s -- as well as much of Kaptur's territory around Toledo. Dennis may be out for now, but don't assume we've seen the last of him. After all, he miraculously recovered from his tumultuous term as mayor, and he has been rumored to be eyeing a House district in Washington state as a post-loss move. --DG
11:37 p.m. Yes, Idaho voted with coins dropped into buckets. If you've been following the race on Twitter tonight, you know that Idaho's GOP caucuses put Iowa's little scraps of paper system to shame by using coins deposited in buckets as a vote-counting mechanism. But did you know some of the votes were also supposed to be counted by weight? Sorted with a sawed-off length of pipe designed to fit 100 coins? Tallied by a coin-sorting machine on loan from a bank? The GOP caucuses in Idaho were the state's first; until this year, Republicans there have generally held a May primary. (Democrats have been holding caucuses in the state since 1980.) This March 3 Moscow-Pullman Daily News story (from Moscow, Idaho), explains some of the unusual vote-counting plans in the state this year as local Republicans made their maiden foray into caucusing:
In Payette County, they'll be using a sawed-off plastic pipe long enough to accommodate 100 coins to expedite tallying. In Canyon County, Idaho's second-biggest by population, caucus participants will cast their support for a candidate by dropping coins in a bucket. The buckets will be weighed instead of hand counted.
Ada County considered weighing coins, too, before bankers offered to loan Republicans in Idaho's most-populous county a machine.
"We've looked at both options, but I think we've decided on coin counting," said Ada County Republican Chairman Dwight Johnson. "They're very fast."
The voting coins are not legal tender, but brass tokens handed out to voters when they arrived at caucus locations, which have "an outline of Idaho flanked by GOP elephants on one side, and an eagle and shield on the other," according to the Idaho Statesman. --GFR
11:11 p.m. A nervous man. Santorum Press Secretary Alice Stewart tweets this photo of Rick Santorum and his entourage (that appears to be Mike DeWine leaning over him) watching the results come in.
11:01 p.m. Romney wins Idaho. Meanwhile, Fox News has called the Idaho caucuses for Mitt Romney. With a large Mormon population, the state was expected to be a good one for him. It too soon to tell whether Ron Paul (remember him?) or Rick Santorum will come in second. Paul's campaign had argued it would do well and might even pull off a win. --DG
10:56 p.m. Still too close to call in Ohio. It's starting to look like Mitt Romney might pull out a win in Ohio, although it will be a very weak one. While Santorum had a solid lead earlier, that vote excluded major urban centers, especially Cleveland and Cincinnati, that hadn't reported yet. As those totals come in, Romney appears to be pulling back ahead. But NBC isn't taking any chances:
@ChuckTodd reports NBC News will NOT call Ohio TONIGHT.— Domenico Montanaro (@DomenicoNBC) March 7, 2012
10:08 p.m. Santorum wins North Dakota. While we wait for Ohio results to come in, numbers from farther west are finally arriving. CNN now projects that Rick Santorum has won the North Dakota caucus, his third win of the night. --DG
9:31 p.m. Looking tight in Ohio. As Rick Santorum speaks in Steubenville -- joined on stage by his 93-year-old mother -- the Buckeye State race looks extremely tight. The results are streaming in slowly, but Santorum and Romney are neck and neck. Howard Fineman reports that the campaign was trying to lower expectations earlier today. But Boston also has its eye on the area around Cleveland, according to Politico's Reid Epstein:
Told Romney high command has its eyes on Cuyahoga County. Metro Cleveland is where they think they can build enuf advantage to win state.— Reid Epstein (@reidepstein) March 7, 2012
9:00 p.m. Newt Gingrich: "I am the tortoise."