From this morning's Earlybird:

• "Pennsylvania Sen. Arlen Specter's switch to the Democratic Party underscores the clout of Club For Growth, a conservative group that targets Republicans it brands insufficiently committed to low taxes and small government," the Wall Street Journal reports. "Mr. Specter fingered Club For Growth as the key factor behind his decision, saying he would have lost the Republican primary to a Club-backed rival. His decision has prompted some Republicans to turn on the organization, saying it backs those who are so conservative that they then lose to Democrats."

• "Despite moves by Senate Republicans to downplay expectations of a battle royal over the next Supreme Court nominee, conservative judicial activists are increasing pressure on their Congressional allies to oppose a liberal jurist," Roll Call (subscription) reports. "Though it's unclear just how soon President Barack Obama will name Justice David Souter's replacement, groups such as the Third Branch Conference, the Judicial Confirmation Network and the Committee for Justice are mapping out their strategy to rally Senate Republicans' appetite for pushback."

• "Union groups are targeting one of their close allies in Congress over a controversial proposal to tax employee healthcare benefits," The Hill reports. "In a coordinated campaign using radio advertising, mail and other pressure mechanisms, three top unions are urging Oregonians to voice their displeasure to Sen. Ron Wyden (D-Ore.), whose proposal may be stalled in the Senate."