One of the go-to websites for political junkies has always been 538, Nate Silver's poll-related work now published by the New York Times.

Today Silver says Barack Obama has a slight, tenuous lead in the race for 270 electoral votes.

As Mitt Romney campaigns in St. Louis, though, Silver suggests Obama's chances in the state are pretty slim. He gives Romney a 78% chance of carrying the state in November, with Obama at 22%. (If the election were held today, the story says, Romney would have a 92% chance in Missouri. He's got a 100% chance today of winning Kansas.)

His November projection: Romney 52% of the state's vote, to Obama's 46%.

That projection says something important about the national race. In 2008, Obama and John McCain fought to a virtual tie in Missouri (McCain eventually won the state's 11 electoral votes), which means the GOP ticket did about 6 points better in the state than it did nationally.

If Missouri is now +6 for the GOP ticket -- and assuming the state follows the 2008 trend -- the national popular vote should be tied, roughly, in November.

Put another way: McCain was +6 in Missouri in 2008 -- six points better than his national vote. If Romney does six points better in Missouri than his national vote -- and he's leading by 6 -- the national vote is likely tied.