Sen. Arlen Specter's announcement that he would switch parties to pursue reelection as a Democrat drew surprise quickly from his Democratic Senate colleagues.

A one-word response characterized Democrats' response: "Wow."

Sen. Claire McCaskillClaire Conner McCaskillNSA spying program overcomes key Senate hurdle Senate campaign fundraising reports roll in Dems search for winning playbook MORE (D-Mo.) tweeted:
Specter to switch parties? Wow.


Sen. Bill NelsonClarence (Bill) William NelsonSenate campaign fundraising reports roll in Week ahead: Tech giants to testify on extremist content Puerto Rico's children need recovery funds MORE (D-Fla.) shortly followed up:
Whoa, Arlen Specter is switching to Democratic Party after three decades in GOP


The surprise announcement was met with shock well beyond the walls of Congress, however. Tweets from bloggers, pundits, and journalists all expressed surprise at the announcement today.