Arlen Specter isn't waiting for Pat Toomey, the former GOP Congressman who nearly defeated him in the 2004 primary, to officially enter the race this time -- he's already going on the air with an attack ad.

The ad blasts Toomey as a credit-default swap trader who favored less oversight of Wall St. and putting Social Security in the stock market, and now wants a "bonus" in the form of a U.S. Senate seat:

Toomey has said he's "very likely" to run, but hasn't officially launched his campaign. That said, he's been speaking to conservative activists -- even appearing with Joe The Plumber against the Employee Free Choice Act -- and a candidacy really appears to be a foregone conclusion. So Specter isn't waiting.