It's not a given that Obama will win the 20 states that John Kerry won in 2004. He might lose New Hampshire and Pennsylvania. So let's assume Obama has 18 states in the bag.

I don't think Obama is going to be hosting rallies in any of the solid blue states (New York, New England, Washington, Oregon, California). His focus will be on the battleground states. And of those, Obama just needs four of them. The four states he seems to be focusing on are Colorado, Virginia, North Carolina, and Iowa. If he wins those and retains Pennsylvania and New Hampshire (or picks-up additional battleground states like New Mexico, Indiana, and Ohio) then he's our 45th president.

In other words, this is Obama's race to lose. John Dickerson of Slate gives us the big picture:

Here's where things stand: If you look at the latest national polling, Obama is up by an average of about five points. That gap may shrink if McCain gets a bounce from his convention, but with each passing day, national numbers are increasingly meaningless. What's most important now is how things are going in the battleground states. In those states, things look much better for Obama than they do nationally. If you look at the pollster.com map of state polling, Obama has 260 of the 270 electoral votes he needs. John McCain has 186.

If current trends hold, Obama needs only to pick up Virginia and Colorado, two states where he's ahead, where trends favor him, and where he won in the primaries. Obama is not only ahead in all the states John Kerry won, he's virtually locked down Iowa, a state George Bush won. (He's ahead by 15 in the latest CNN poll.)

McCain's best chances to pick up states John Kerry won in 2004 are New Hampshire, where he is tied with Obama, and Michigan and Pennsylvania, where Obama is ahead just outside the margin of error. Yet even if McCain can reverse the trends in those states, he's still only at 241 electoral votes. So he also needs to keep Ohio and Florida in the GOP column (polls are even there) and not give up any of the other states, like North Carolina.