Arlen Sphincter continues to make friends on the other side of the aisle

Once again, Karma's a bitch.

Now it's MoveOn that has the democrat-turned-republican-turned-back-to-democrat in their sights.

One of the nation’s largest liberal advocacy organizations, MoveOn.org , is resisting efforts to clear the Democratic primary field for Republican-turned-Democratic Sen. Arlen Specter.

The political arm of MoveOn flexed its muscle Friday by releasing the results of an online poll that showed the vast majority of the group’s roughly 170,000 members in Pennsylvania — 85 percent — would consider supporting a Democratic challenger against Specter.

The group expressed concern over Specter’s vote against President Obama’s $3.4 billion budget just one day after defecting to the Democratic Party. MoveOn also cited comments Specter made in an appearance on “Meet the Press” last weekend suggesting he would oppose a public health insurance option that some Democrats would like to see included in any health care reform proposal.

Now that the gauntlet has been thrown down, expect Specter to begin tacking left; er, uh -- further left.