Nationwide polls in April on the presidential election in November are meaningless, except as barometers of how news stories or controversies are affecting the campaigns. Early state by state polling is a bit more useful, though not much.

Still, one interesting phenomenon shines through in SurveyUSA’s sampling of presidential preferences in 14 states: Despite (or because of) the media’s relentless coverage of the Democratic race — and despite record turnout among Democrats — a dramatic shift toward the Dems in Red states has yet to materialize.

Three states show potential for a shift from Red to Blue, and in Wisconsin, McCain would tie Clinton. (These states are indicated in purple). Among the three potential Red-to-Blue shifts, Obama would take Iowa, and Clinton is ahead of McCain by 1 point in Missouri but would trounce him by 11 percentage points in Ohio:

What this may indicate is that, in the greater scheme of things, it doesn’t really matter which Democratic candidate wins the nomination. The election will play out along partisan lines.

What it portends is that, unless something dramatic happens — for example, if McCain were to have a “macaca” moment that seriously hobbled his campaign — Barack Obama, the putative nominee now, will face a challenge in the fall that is very similar to the campaigns of the last two cycles — Red states vote for McCain, Blue states go for Obama, leaving the Electoral College about even so that voters in a swing state, like Florida in 2000 or Ohio in 2004, ultimately decide the election.

If so, the best hope for the Democrats — and, by any rational measure, for the future of the United States — is that the swing state this year is Ohio, where the Republican Party remains weak and unpopular in the wake of corruption scandals.