When I first considered Barack Obama’s re-election chances in this magazine, last November, he was about a 50-50 contender against the Republican field. As I noted then, this was an unusual spot for a sitting president. A year before their own re-election races, Roosevelt, Eisenhower, Nixon, Reagan, Clinton and both Bushes were all favored. One year out, it seemed as if things could break either way for the president in 2012.

Six weeks before the election, the picture is much clearer. While Obama’s postconvention bounce gave him a lead of four to five points over Mitt Romney, most of the polls before the conventions had the vote split by two or three percentage points. If Obama’s bounce fades and the two-to-three-point trend holds till Nov. 6, it’s conceivable that either candidate could pull a George W. Bush and win the Electoral College despite losing the popular vote. This puts the emphasis on what I call “tipping point” states. Obama and Romney can hope for good jobs numbers or terrible ones, and for calm in the Middle East or an eruption that hurts the administration. But one thing they can definitely control is how to allocate their resources­ for the best chance at 270 electoral votes.

Using my FiveThirtyEight model, I’ve determined — through about 25,000 simulations that I run each day — which states could put either candidate over the top. Crucially, the model takes into account not only how states poll relative to national trends but also to one another. Demographically similar states can rise and fall together. If Romney makes gains in Wisconsin, for example, he will probably also do so in neighboring Minnesota.

Perhaps more important, the program evaluates the order in which the states might line up. Obama could win North Carolina, where the polls show a competitive race, but he’s unlikely to do so without already having won Ohio, Florida and Virginia, where the demographics are slightly more favorable to him. Some combination of those states would probably get him to 270 electoral votes anyway. By that point, North Carolina would be redundant.