Organized labor is targeting the Democrats’ new convert, Sen. Arlen Specter, in a TV advertisement on the Employee Free Choice Act.

The spot, “The Right Thing,— is the first of its kind since Specter announced two weeks ago that he was switching parties. According to a spokesman from American Rights at Work, the group airing the ad, it is saturating the cable and network stations statewide in Pennsylvania.

Specter originally voted for cloture on the EFCA in 2007, but he said in a floor speech earlier this year that he planned to vote against ceasing debate on the bill backed by unions this Congress, which would effectively kill the legislation in the Senate.

“Pennsylvania backed Specter when he was the deciding vote for President Obama’s stimulus package,— says an announcer in the spot. “It’s already bringing new jobs. Specter usually does the right thing. Two years ago, he supported the Employee Free Choice Act, to help working people join together for fair pay and benefits. So now, where will Specter stand? With Obama, Biden and the working families of Pennsylvania? Or with greedy CEOs and big-business lobbyists? Call and tell Specter Pennsylvania’s for him. As long as he’s for the Employee Free Choice Act.—

When Specter announced his decision to switch parties, national Democrats welcomed him, and the Democratic Senatorial Campaign Committee endorsed him. But since his announcement, things have been less than favorable for Specter: Senate Democrats announced that the nearly 30-year Senator will not retain his seniority this Congress, and several Democrats are considering challenging him in the primary.

Former National Constitution Center President Joe Torsella is still running for the Democratic nod, and Rep. Joe Sestak (D) — a vocal EFCA supporter — has recently said he is seriously thinking about running.