But perhaps no state is being more closely watched than Pennsylvania, where long-time senator Arlen Specter is in real danger of not securing the Democratic Party nomination. (I would be remiss in not acknowledging that Kentucky also has a heated primary election.)
Just how worried is Specter? Consider this "tweet" he sent out at 7:00, the time the polls in Pennsylvania opened:
The polls are open - make sure you get out and vote today.
Politico.com notes that Specter -- who, based on the last polls I saw was essentially tied with his challenger, Rep. Joe Sestak -- is considered to be in enough trouble that President Obama doesn't want to campaign for him. TIME magazine suggests today could be the day that Specter and several other "bums" are sent a tough message -- but no one is quite sure what that message is.
Though I'm in Washington taking part in The Washington Center's "Top Secret" program, I'm doing my best to track what happens across the country. I'll update and comment as I can.