As this week's Census report showed, the sunbelt states have continued to grow -- and now political power keeps shifting along with the populous. With the new Electoral Vote and congressional seat tallies for 2012, several Republican-leaning states of the South and West have gained, while the Democratic-leaning states of the northeast have lost. That means the presidential math just got a little harder for Democrats, and a little easier for the GOP.
The new map will put a little more emphasis on southern battlegrounds like Florida at the expense of older battlegrounds like Ohio and Pennsylvania, both of which have lost seats and votes. In the 2012 election, this could be a determining factor; in a close election that resembles 2000 more than 2008, it will be the determining factor.
Working from 2008 results, Republicans would tally at least six more electoral votes simply by winning the same states that John McCain won. The standout here is Texas, which is the biggest gainer among all states in the union with four.
Meanwhile, reflecting the disparity in growth between the sunbelt and the northeast and rustbelt, some states where Democrats often win (and which Obama won handily) have all taken loses. The Democrats would collect six fewer electoral votes for their easy wins in these states now; electoral votes would go from 365-173 to 359-179.
And the battleground power is shifted. Florida and North Carolina, each hotly contested in 2008, are gainers, assuming that the Obama campaign can again put these in play. And Nevada, which Mr. Obama won easily, could for now wind up back in battleground status. In sum, that's three more electoral votes to be won in these tough contests.
But Ohio (losing two) and Pennsylvania, which are often synonymous with swing state action, are now less valuable, along with Iowa, which (although Mr. Obama won it easily) has been in play in recent elections and certainly could be again in this environment.
Thinking of impact, in a hypothetical close election, this could matter a lot. Consider scenarios under the new apportionment that subtract some states that Mr. Obama flipped red to blue in 2008 (and which could at least be battlegrounds again) from the Democratic totals, and it puts much more emphasis on smaller battlegrounds like New Hampshire and New Mexico. It also brings the Democratic total much closer to 270 under the new apportionment, but still with breathing room under the old.
If, hypothetically, Democrats lose Indiana, Florida, North Carolina and Virginia next time, Mr. Obama is under 300 but could still win if he loses Ohio, too. But he would lose if he also were to lose New Hampshire, Iowa or Colorado. If Mr. Obama were to lose New Mexico, Iowa, New Hampshire and Colorado, he would now lose the election, even if he were to win Ohio. If he wins all of those states including Ohio, and loses Pennsylvania, his margin of error disappears.
In fact, consider what these shifts could mean in a very close election by comparing it to 2000, the tightly contested Bush versus Gore contest. Mr. Bush would have won 283 electoral votes under the new arrangement, and hence, even had he lost New Hampshire, a close state that he won, still would have had an electoral vote majority. Had he won Wisconsin and New Mexico, two extremely close states, he would have had an electoral vote majority even without winning Florida.
That close contest was the last held under the redistricting of the 1990's. So since the 2000 election, the shifts in electoral vote power toward the sunbelt look even more dramatic.
In the next part of this analysis we'll look at congressional districts and how they could be affected.
Anthony Salvanto is CBS News Elections Director. Mark Gersh is Washington Director, National Committee for an Effective Congress, and a CBS News Consultant.