This is your weekly update on the polling data. I didn’t give an update last week because I wanted to wait until John McCain’s post-convention and post-Palin bounce settled down. A lot of Barack Obama supporters were starting to panic as the polls swung toward McCain over the last week and a half, but now things have begun to settle down.

On the national level, the tracking polls that last week showed McCain with a small lead are now showing Obama with a small lead again. The last four national polls, all taken this week, respectively show: Obama +5, Obama +2, McCain +2 and Obama +3. Only the most recent poll is outside the margin of error, so on a national level this is still a very, very tight race.

Unfortunately, there aren’t a lot of new state polls out since last week that might reflect that change. The most recent poll in Ohio shows Obama with a 2-point lead, but that’s the first poll in quite some time to put Obama ahead. We’ll have to see if subsequent polls bear that out or if the pattern returns to McCain with a small lead in that key state.

In other key swing states, the race has tightened considerably. In Pennsylvania, Obama’s lead has shrunk to well within the margin of error and the most recent poll showed a tie. In Michigan, there have been no new polls since last week, but one poll showed McCain with a 1-point lead, the first time in a long time that McCain came out ahead in a poll in this state.

Virginia remains very tight. There was one poll in that state that showed McCain with a 9-point lead, but that was a small poll (a sample of only 500) and it was of registered voters rather than likely voters. The other three recent polls either show the candidates tied or Obama with a small lead. If Obama could turn Virginia, that would be a huge turn of events.

In Florida, McCain had gotten a good bump after the convention, but the most recent poll shows a tie. It still seems like a long shot for Obama to win Florida, but he’s definitely competitive there. Colorado has gotten much closer as well, with McCain showing a 2-point lead in the most recent poll, but that was four days ago. We’ll have to see if the newer polls show McCain’s bounce losing steam in that key state.

New Mexico seems to have flipped back to Obama after one poll showed McCain with a 2-point lead last week. The most recent poll shows Obama with an 8-point lead. Iowa remains strongly for Obama; McCain basically got no bounce there at all.

All in all, the swing states are still the swing states and things have tightened up. Now that the McCain bounce from the convention and the Sarah Palin pick seem to have settled down, the polls over the next week should be very important to watch. I expect them to slide back a bit more, with Obama gaining back some of what he lost in Pennsylvania and Colorado. The real question is, can he keep up the momentum in Ohio and Virginia? If things continue to move in his favor in those states, that spells real trouble for McCain. Either way, this is going to be a very close election.