A lot has happened in the past week in regards to the PA Senate race:

First, a new Keystone Poll shows Arlen Specter is not all that popular:

The strong backing of Democratic Party leaders has done little to change slumping public support for the party's newest convert, U.S. Sen. Arlen Specter. Only 28 percent of all those surveyed say that he deserves re-election, according to the latest Keystone Poll, and double that number say it's time for a change.

....

Back in March, before the switch, roughly half the voters in each party said that Specter was doing an "excellent" or "good" job in the Senate.

Those numbers have plunged in the latest survey. Whereas 57 percent of Democrats gave him good or excellent ratings in March, only 46 percent rate him as highly now. Among Republicans, 49 percent rated his job performance as good or excellent in March, and only 18 percent gave him those ratings last week.

The support that is he somewhat holding onto is that of Democrats. If there is a real primary, or if Arlen doesn't come out strong for the Obama agenda, those numbers will sink, too. Further, in a match up against Sestak (with a very big MoE), the poll has it at 33-13. For an ultra incumbent like Arlen, being that much below 50 percent is very, very dangerous, and adds to worrisome trend lines in polls of the race:

And that is without Sestak doing any campaigning... Sestak is edging ever closer to a run. Word is that he will not announce for a month or two, but, he has made it pretty clear that he is in.

While that Keystone poll was in the field, Arlen was supposed to speak at the convention of the United Steelworkers. They dis-invited him. (Read this whole post, because it is pretttty funny.) If labor leaves him, he is really screwed.

Given all of that, and in an attempt to head left, he recently said that he is for a public health care option, after scoffing at it right after he switched parties. No one said Arlen wasn't good at making you a little dizzy.

On the Republican side, ultra-right Pat Toomey has effectively been cleared for the general election, as local Congressman Jim Gerlach has said he will not run.