Here's the key finding from yesterday's NBC/Wall Street Journal poll: "Sen. Obama leads ... among older voters, those over 65 years old, by nine points, erasing a one-point McCain advantage from the last poll."

Why so key? Because, as First Read notes this morning:

So many pundits and analysts are wondering why McCain is continuing to push for Iowa and Pennsylvania, despite the daunting poll numbers in those two states. There are two reasons. First, he's run out of options. If you assume Colorado is gone and that Virginia is teetering, he has to find 270 EVs somewhere. Second, Iowa and Pennsylvania are two of the oldest states in the union, as far as the age of their populations. Both states have tons of seniors, and if McCain can turn things around again with seniors, he should see movement first in these two states.

Also, here's your special Palin bonus from the same poll:

The one candidate whose popularity has fallen is Gov. Palin: 38% see her positively, down from 44% two weeks ago; 47% see her negatively, up 10 points from the last poll. That's the highest negative rating of the four candidates. Fifty-five percent of voters say Gov. Palin is not qualified to be president if the need arises, up from 50% two weeks ago.

--Noam Scheiber