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 McCaskillA Cabinet position for Petraeus; disciplinary actions for Broadwell after affair Defense bill tackles retaliation against military sex assault victims Red-state Dems face tough votes on Trump picks MORE (D-Mo.) tweeted:
Specter to switch parties? Wow.


Sen. Bill NelsonBill NelsonRed-state Dems face tough votes on Trump picks Feds allow GM to delay airbag recalls Florida governor won't serve in Trump administration 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.