Statement by Senator Arlen Specter  —  I have been a Republican since 1966.  I have been working extremely hard for the Party, for its candidates and for the ideals of a Republican Party whose tent is big enough to welcome diverse points of view.  While I have been comfortable being a Republican, my Party has not defined who I am.

Two Republicans blame conservatives  —  Two leading Republicans say Sen. Arlen Specter's decision to become a Democrat highlights the hostility moderates feel from an increasingly conservative GOP.  —  “You haven't certainly heard warm encouraging words about how [the GOP] views moderates …

Specter: ‘The disappointment runs in both directions’  —  WASHINGTON (CNN) — Veteran Pennsylvania Sen. Arlen Specter said Tuesday that he switched from the Republican to the Democratic Party.  —  “I know I'm disappointing many of my colleagues,” he said at a news conference.

Unprincipled Hack (D-PA)  —  When a politician switches parties, it's customary for the party he's abandoned to denounce him as an unprincipled hack, and the party he's joined to praise him as a brave convert who's genuinely seen the light.  But I think it's pretty clear that Specter is an unprincipled hack.

Specter switching parties  —  A source involved in the talks confirms that Senator Arlen Specter will switch to the Democratic Party, a dramatic move putting the Democrats within reach of two votes in the Senate.  —  The move stands to put the White House's agenda on a fast-track …

Specter Switches Parties  —  Senator Arlen Specter of Pennsylvania said on Tuesday he would switch to the Democratic party, presenting Democrats with a possible 60th vote and the power to break Senate filibusters as they try to advance the Obama administration's new agenda.

Snowe: GOP Has Abandoned Principles; Specter Switch “Devastating”  —  Sen. Olympia Snowe of Maine, one of the few remaining moderate Republicans in the Senate, said Tuesday that Arlen Specter's abandonment of the GOP is “devastating,” both “personally and I think for the party.”

Specter move caught GOP leaders by surprise  —  Senate Republican leaders said they had received no heads-up from Sen. Arlen Specter (Pa.) about his decision to leave the Republican Party and run for reelection as a Democrat.  —  Specter told Senate Majority Leader Harry Reid (D-Nev.) …

Another Triumph for the Club for Growth  —  With Arlen Specter's defection, all that stands between the Democrats and a 60-seat Senate majority are Norman Coleman's lawyers.  I wish them every success - but they have not exactly been on an winning streak to date.

Limbaugh to Specter: Please take McCain with you  —  (CNN) — Conservative host Rush Limbaugh said Tuesday he isn't sorry to see Arlen Specter leave the GOP — and that many Republicans wish the Pennsylvania senator would take a few others with him when he goes.

Specter: I'm not an automatic 60th vote  —  Arlen Specter has crushed Republican spirits while causing Democrats to rejoice, but his stunning party switch came with a warning label: The Obama agenda isn't suddenly a slam dunk just because he's a Democrat now.  —  “I will not be an automatic 60th vote,” Specter said Tuesday afternoon.

Why Specter Did It — And Had To Do It  —  So why exactly has Sen. Arlen Specter (R-PA D-PA) switched parties?  —  It really comes down to electability — specifically electability as a Republican.  Specter's own statement acknowledged that his support for the stimulus bill has made his position untenable with the GOP:

Limbaugh To Specter: Take McCain And His Daughter With You  —  Reaction from top GOP officials to the defection of Sen. Arlen Specter has been decidedly mixed.  The less orthodox are interpreting the news as a validation of their biggest concerns, while the dyed-in-the-wool types wave ‘good riddance.’