WASHINGTON - Departing Sen. Arlen Specter, D-Pa., yesterday said conservative Republicans who backed tea party challengers against establishment candidates in the recent elections engaged in political cannibalism.

In his final floor speech after three decades in the Capitol, the Republican-turned-Democrat complained there's scant room for centrists like himself in a polarized Senate where civility is in short supply.

"In some quarters, compromise has become a dirty word," said Pennsylvania's longest-serving senator, who lost in the Democratic primary to U.S. Rep. Joe Sestak.

Specter complained that some GOP senators had helped tea party challengers beat incumbent Republicans like Utah Sen. Bob Bennett and Rep. Mike Castle, who lost in the Delaware Senate primary.

"Eating or defeating your own is a form of sophisticated cannibalism," he said.

Specter said the re-election of Alaska Sen. Lisa Murkowski on a write-in vote against the tea party challenger who toppled her in the primary may show the way to "counter right-wing extremists."

Specter, 80, has been a fixture in American politics, emerging as a prominent centrist who used his willingness to cross party lines on key votes as a way to boost his clout in Congress. Specter has overcome a brain tumor, cardiac arrest following bypass surgery and two bouts with Hodgkin's disease.

The former prosecutor said his words were a "closing argument to a jury of my colleagues" rather than a farewell address.

Specter recalled his earlier years in the Senate when there were considerably more moderates in both parties.

"That's a far cry from later years when moderates could fit in a telephone booth," he said.

Many of his Democratic colleagues were on hand for his speech, along with a few Republicans, including Murkowski and Maine's Olympia Snowe, a leading moderate.

Specter lost the Democratic primary to Sestak after taking the risky step of switching from the GOP in his bid for a sixth term.

Specter would have faced a tough Republican primary challenge from Pat Toomey, who went on to beat Sestak on Nov. 2.