The Pew Charitable Trusts

It is among the most commonly repeated refrains during gubernatorial election cycles: The party that wins a state's governorship has a clear advantage the next time presidential ballots are cast.

Governors, the thinking goes, can motivate their party's faithful. They can use the visibility of their office to drive turnout and put White House contenders in a strong position to win. And they are particularly important in large, closely fought states such as Ohio, where the gubernatorial contest captured the money and attention of national Democrats and Republicans alike this campaign season.

In fact, the notion that governors are crucial in determining who moves to 1600 Pennsylvania Avenue is a "media myth," according to a new report from the University of Minnesota's Smart Politics blog .

"A Smart Politics analysis of 550 statewide presidential election results dating back to 1968 finds there to be no correlation between states won by Democratic and Republican presidential nominees and the partisan control of the governor's mansion," the report says. "Democratic presidential candidates have won virtually an identical percentage of states in which they have held control of the governor's mansion (33.8 percent) as those in which Republicans had control (32.2 percent). Likewise, success for Republican nominees has been essentially the same in state with GOP governors (67.3 percent) as those with Democratic governors (65.2 percent)."

The findings, which were first reported by Politico , are sure to encourage Democrats, who earlier this month lost the governorship not only in Ohio, but in Florida, Pennsylvania and Wisconsin and other battleground states as well.