[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/04/28/art_arlen_specter_gi.jpg caption= "Sen. Arlen Specter was expected to face a tough primary challenge in 2010."] WASHINGTON (CNN) – Veteran Pennsylvania Sen. Arlen Specter told colleagues Tuesday that he switched from the Republican to the Democratic Party, Sen. Harry Reid says. The Specter party switch would give Democrats a filibuster-proof Senate majority of 60 … Continue reading Longtime GOP Sen. Arlen Specter becomes Democrat