How long will Election Day last in Ohio?

— -- COLUMBUS, Ohio—Tightly knotted Ohio has become this year's making-of-the-president state, pivotal to the White House strategies of Barack Obama and especially Mitt Romney. Amid all the victory hype by both sides, Republican and Democratic insiders surprisingly agree about the idiosyncratic rhythms and odd contours of election night in the Buckeye state.

Based on bipartisan interviews conducted with the promise of no-quotes-please anonymity, I have put together this likely scenario for election night return-watching in Ohio:

Around 8:30 p.m. (the Ohio polls close at 7:30 p.m.), the first big wave of returns will sweep onto the tote boards. These are the absentee ballots and early votes (maybe 35 percent of the statewide total of about 5.8 million) that the Democrats have been particularly aggressive in harvesting. At this moment, Obama will almost certainly hold his biggest Ohio lead of the evening in percentage terms.

That Obama margin will dwindle throughout the evening as the returns from Ohioans who waited until Election Day to vote are added to the total. By 3 a.m. Wednesday, when virtually all the statewide votes have been tallied, Romney may have moved into the lead. Does that mean that the Republicans can claim Ohio's 18 electoral votes?

Tune in to ABCNews.com on Tuesday, Nov. 6 for livestreaming coverage of Election 2012. Our Election Day show kicks off at noon, and the Election Night event begins at 7 p.m.

Not so fast. For in the wee hours Wednesday morning, the counties will begin their count of the provisional ballots. These are votes that have been challenged for a wide variety of legitimate reasons. They include: Ohioans who are not registered; registered voters who moved but failed to update their addresses; people who showed up at the right polling place but were directed to the wrong precinct; voters who did not bring proper identification to the polls; and those who requested an absentee ballot but decided to vote in person.

Before anyone shouts, "Voter suppression," please understand that the bulk of these provisional ballots eventually will be counted. In 2008, around 80 percent of the provisional ballots were ultimately accepted and that figure rose to about 90 percent in the 2010 gubernatorial race. Recent Ohio history has shown that the provisional ballots tilt strongly Democratic when they are finally tallied. And that is what could make Republicans very nervous as Tuesday night flows into Wednesday morning.

The rough Republican rule of thumb is that Romney requires a statewide lead of, at least, 50,000 votes to survive the provisional ballot phase of the Ohio long count. The requisite election night margin for Romney may, in fact, need to be higher. It all depends on the number of provisional ballots plus valid absentee ballots (postmarked Monday or earlier), which are still in the mail. And despite the best efforts of the secretary of state's office to release an accurate count of disputed and missing ballots Wednesday morning, the final numbers will probably trickle in from Ohio's 88 counties over the following few days.

At this point, under some plausible scenarios, neither Obama nor Romney may be able to claim the White House without Ohio's 18 electoral votes. Despite the whole-world-is-watching drama, events onstage in Ohio will begin to unfold at the pace of Freudian analysis.

Nothing will happen in public for 10 long days as the counties assess the validity of each provisional ballot. Finally, between the 11th and 15th day after the election (Nov. 17-21), counties will begin tallying the results from the accepted provisional ballots—unless, of course, there are further delays from legal challenges.

Small wonder that at least one Ohio election lawyer is already half-seriously worrying about his holiday trip out of state. No, not for Thanksgiving—for New Year's Eve.

Now, from what I have seen on the ground in Ohio, the single campaign event that best emblemizes the micropolitics of the battleground state over the past few days was Obama's late Friday afternoon rally at Lima Senior High School.

Incumbent presidents rarely come to Lima (pronounced like "lime" rather than the city in Peru). It's a gritty, industrial town (population: 39,000) in a Republican county on the southern fringes of the Toledo media market. This is not a standard political destination—especially four days before an election.

Sure, Harry Truman whistle-stopped through Lima in mid-October 1948, promising in a five-minute speech from the back of his campaign train, "I'm going to take the hide off [the Republicans] from head to toe." And Ronald Reagan, borrowing Truman's Pullman railroad car and his itinerary, told a trackside rally four weeks before the 1984 election that Democrat Walter Mondale was "taxing my patience" and everything else.

But that was pretty much it until Obama got away from the railroad tracks to hold a full-throttle campaign rally here. Addressing more than 3,500 area Democrats, Obama highlighted another form of transportation as he declared, "Look, I understand Gov. Romney has had a tough time here in Ohio because he was against saving the auto industry."

What mattered, though, were not the president's words, but his physical presence. The Obama visit was designed to wring every last vote out of Allen County (Lima and the farmland that surrounds it), where the president received just 19,522 votes in 2008. The morning-after front page of the Lima News underscored the benefits of this small-town strategy: The Saturday front page was all Obama, and featured three photographs of the president and the banner headline, "BETTING ON HOPE."

If Obama wins Ohio, where he has been leading in almost every published poll for the past month, Democrats have a three-part explanation. "The first reason would be the auto industry bailout," said veteran Ohio political strategist Greg Haas, who now heads the Franklin County (Columbus) Democratic Party. "The second reason is the auto industry bailout and the third reason is the auto industry bailout."

That is, of course, an exaggeration. Other pro-Obama factors include the fast-recovering Ohio economy (the statewide unemployment rate is down to 7 percent) and the politically successful demonization of Romney as a job-destroying businessman with Cayman Islands bank accounts and a disdain for 47 percent of the nation. In addition, an NBC News/WSJ/Marist poll, released Saturday, found that a whopping 73 percent of Ohio voters approve of the president's handling of the aftermath of Hurricane Sandy.

But the revival of the Ohio auto industry is key. Not only is the venerable Lima Ford Engine Plant expanding, but so is the nonunion Honda plant in nearby Anna (Shelby County). After the Obama speech, Mike Knisley, from the local Pipefitters union who is president of the Ohio building trades council, gushed about the construction jobs that are being created at the Ford plant: "I've got 200 tradesman out there working right now."

When asked about Obama's long-standing problems with blue-collar white male voters in places like Lima, Knisley volunteered an explanation: race. "It's the race thing that I just addressed with my apprentices last night," he said. "I told them that they just had to get over it."

As darkness fell over Lima late Friday afternoon, there was only one possible next stop for many Democrats from the Obama rally. It was the nearest branch of Kewpee Hamburgers, a Lima institution that is part of the remnants of America's second-oldest burger chain. (Columbus-based White Castle is slightly older, but there is no comparison between the taste of cardboard and a genuine Kewpee burger.)

It was at Kewpee that I interviewed for the first time during the entire campaign the political version of the unicorn—a 2008 John McCain voter who is switching to Obama. Her name is Marcy Hughes, and she runs a branch library and lives in the nearby hamlet of Harrod. The mother of two sons (one studying at the Lima branch of Ohio State and the other recently graduated from college), Hughes is attracted by Obama's support of the federal student loan program.

But even though her husband (who missed the Obama rally and dinner at Kewpee) is the type of small-business owner lionized by Romney, Hughes does not relate to the GOP nominee's "You built that" rhetoric. In fact, she doesn't relate to Romney at all: "I don't feel that he's for the middle class. And that's what we all are around here."

During what promises to be a very long night Tuesday in Ohio, I will be looking at the returns from the Lima area. And thinking about how the 2009 decision to rescue General Motors and Chrysler may well have saved Obama's presidency.