One week from Election Day, the presidential race has tightened dramatically in Ohio, which appears more likely than any other state to decide who will win the White House.

A Rasmussen Reports survey released Monday shows Mitt Romney overtaking President Obama in Ohio for the first time since May, with 50 percent support to Obama's 48. This follows a Cincinnati Enquirer/Ohio News poll over the weekend that showed the candidates tied at 49 percent.


The RealClearPolitics average of polls still shows Obama ahead, 48.6 to 46.7 percent, but that spread might flatter the president's current position because it includes a CNN-ORC and Public Policy Polling survey, released last week, which showed him up by 4 points, and a Time magazine poll giving him a 5-point lead.

With perhaps only a handful of true toss-up states left, Ohio could prove indispensable for each campaign in their quest for the 270 Electoral College votes necessary for victory.

It could be especially important for Romney, whom prevailing punditry says has a narrower path to victory. No Republican has ever lost Ohio and won the presidency. Without Ohio, Romney would have to run the table of remaining battleground states, and carry Virginia, Florida, North Carolina, Iowa, Colorado, New Hampshire and Nevada.

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Virginia, Florida and North Carolina have moved in Romney’s way, polls suggest, but remain close. Polls in Iowa, Colorado and New Hampshire show the candidates tied. But a growing Hispanic population in Nevada, plus Sen. Harry ReidHarry Mason ReidSenate heads home to campaign after deal on Trump nominees GOP has always been aggressive in trying to weaponize the system of judicial nominations Republicans come full circle with Supreme Court battle to the end MORE’s (D-Nev.) campaign infrastructure there, may already have put that state beyond the GOP challenger’s reach. It is this that makes Ohio so important in Republican efforts to take the White House.

But Obama can scarcely afford to lose Ohio either. With Romney apparently leading in Florida, North Carolina and Virginia, Obama would have to carry New Hampshire, Iowa, Colorado and Nevada if he were to lose Ohio.

But a loss for the president in Ohio would probably spell trouble for Obama in those other must-win states, too. If Ohio goes red, it would probably indicate that he was struggling in other battlegrounds as well. Indeed, polls in states such as Minnesota, once considered a lock for president, have recently tightened along with rest of race.

Both campaigns are talking up their advantages in Ohio, hoping to influence how the race there is perceived and thus produce a snowball effect in voters' minds.

On Monday, the Romney campaign sent out a memo from senior adviser and Ohio state director Scott Jennings outlining what it says is evidence of Romney’s surge there.

“The next-to-last weekend before the election produced fresh evidence of Mitt Romney’s momentum in Ohio and bolsters our belief that Mitt Romney and Paul RyanPaul Davis RyanElection Countdown: Cruz, O'Rourke fight at pivotal point | Ryan hitting the trail for vulnerable Republicans | Poll shows Biden leading Dem 2020 field | Arizona Senate debate tonight Paul Ryan to campaign for 25 vulnerable House Republicans GOP super PAC pushes back on report it skipped ad buys for California's Rohrabacher, Walters MORE are poised to win the Buckeye State’s 18 electoral votes,” the memo read. “The state of the race in Ohio shows a dead heat, with Romney tracking toward victory on Election Day. The daydream Chicago was having a few weeks ago about Ohio coming off the board has been replaced by their nightmare of Romney momentum fueled by our ticket’s performance, our goal-shattering ground game, and an unmistakable feeling among independent voters that Barack ObamaBarack Hussein ObamaChance the Rapper works as Lyft driver to raise money for Chicago schools Americans are safer from terrorism, but new threats are arising Donald Trump Jr. emerges as GOP fundraising force MORE has no plan for the next four years.”

The memo cited the Cincinnati Enquirer/Ohio News poll, the campaign’s grassroots efforts, crowd sizes at campaign events, newspaper endorsements and early-voting numbers.

Romney and Obama each have four newspaper endorsements in the state; The Cleveland Plain Dealer, the Akron Beacon-Journal, the Youngstown Vindicator, and the Toledo Blade have picked Obama, while the Columbus Dispatch, Cincinnati Enquirer, Marietta Times and Warren Tribune Chronicle went for Romney.

The Obama campaign also believes it has a strong grassroots presence in Ohio, but points particularly to what it says is a big advantage with early voters. The campaign circulated a memo this month claiming to be well ahead of Romney among early voters and recent polling seems to back this up. Time magazine's poll last week showed Obama with a two-to-one lead among Ohio early voters.

It may be a late night of ballot counting in Ohio on election night. But if it is not, with the state on Eastern Standard Time, announcement of a winner might could have a heavy influence on voters in many of remaining swing states, where polls will still be open.