In Yesterday’s Wall Street Journal, Karl Rove, former adviser to President Bush wrote that presumptive Republican nominee John McCain

is realistic enough to know he will fall behind Mr. Obama once the Democratic nomination is settled. He’s steeled himself and his team for that moment. And he’s comforted by a belief that there will be plenty of time to recapture the lead. Mr. McCain saw Gerald Ford come from 30 points down to lose narrowly to Jimmy Carter in 1976, and watched George H.W. Bush overcome a 17-point deficit in the summer to hammer Michael Dukakis in the fall of 1988.

The polls are already starting to show this, with Obama inching ahead in most surveys.

Now that the contest for the Democratic presidential nomination is all but over (Jay Cost offers a dissenting view to this conventional wisdom), an Obama surge should suggest his potential for success this fall.

As I learned in researching a previous post on polling, polls in May and June tend to show the candidate of the party out of power running far ahead of the candidate of the incumbent party when that latter party has been in power for eight years.

Yet, in the most recent of those elections (2000, 1988 and 1976), the candidate of the incumbent party was able to close the gap by the November election in 2000 and 1976 while reversing the numbers in 1988 and retaining the White House for his party.

Only one poll (CBS/New York Times which tends to skew in favor of the Democrats) shows Obama with the kind of lead challengers like George W. Bush in 2000, Mike Dukakis Jimmy Carter enjoyed in 1988 and 1976 respectively. But, the month is still young. Next week’s polls should provide a better gage.

Should the CBS/NYT poll be a harbinger and other polls should similar margins for the Illinois Democrat, expect him to be a stronger candidate that some forecast. Still, even if Obama bests McCain by large margins, it will not necessarily be time for Republicans to panic.

Should, however, most polls continue show a tight race, even with Obama slightly ahead, if history is any guide, John McCain should win this fall.

Provided of course, he doesn’t get cocky and runs an aggressive campaign.