Not that long ago, Ohio's primary election March 4 looked like it would be irrelevant to the presidential outcome. Conventional wisdom said the Democratic and Republican nominees would emerge after Super Tuesday on Feb. 5, when more than 20 states ganged up to create a mini-national election.

Of course, not that long ago the conventional wisdom held that Sen. Hillary Clinton and Mitt Romney would be facing each other in November. It's amazing how the smart money -- as well as the pundits and the polls -- can be so wrong so often.

Now the Ohio primary is positioned to be a critical showdown between Clinton and Sen. Barack Obama, with the winner here (and in Texas on the same day) likely propelled to the Democratic nomination. Once again, as with the general election, Ohio will play kingmaker.

Clinton has long been favored to win the primary here. She's done well in the large states so far (New York, Masschusetts, New Jersey and California), and she has the backing of Gov. Ted Strickland and former Sen. John Glenn.

The SurveyUSA poll released last weekend shows Clinton with a 56-39 percent lead over Obama in the state. It's actually the first time Obama has been within 20 points of Clinton in any poll in Ohio since last summer.

But momentum is clearly on Obama's side. He has a chance to win every post-Super Tuesday primary before Ohio voters get a crack at the race.

He won convincing victories over Clinton last weekend in Louisiana, Maine, Nebraska and Washington, and he's poised to do well in the Feb. 12 "Potomac primaries" in Maryland, Virginia and Washington, D.C. (Results weren't known before this issue went to press.)

All that's left before Ohio and Texas are Feb. 19 contests in Wisconsin and Obama's home state of Hawaii. So it's very possible that Obama will actually lead Clinton in the delegate count by the end of the month and thus would be the Democratic front-runner when Ohio votes March 4.

Would that change in status cause voters to switch to him in droves? He's made up 20-point deficits to win several states already.

Several key Democrats have yet to endorse either candidate and are likely to remain neutral for now. Yet if any of them makes a public endorsement -- former Vice President Al Gore, Speaker of the House Nancy Pelosi, former candidate John Edwards -- Ohio voters could be swayed.

It ought to get busy around here in the next few weeks. Look for Obama and Clinton to begin running ads on Cincinnati TV stations and to come to town. Look for the Republican front-runner, Sen. John McCain, to visit Cincinnati to woo former Romney supporters Carl Lindner, Richard Farmer, Jim Orr and Jeff Ruby.

The fun's just starting. Hell, the way things are going, maybe even Indiana and Kentucky voters will have a say in May when their primaries roll around.