Today on Capitol Hill:

The shadow of the old Arlen Specter emerged Wednesday when he echoed Republicans’ concerns that Sonia Sotomayor may say one thing at her confirmation hearing and do another as the next Supreme Court justice.

Sen. Specter, who recently switched parties from Republican to Democrat, expressed frustration over the nominee’s refusal to give specific answers on a number of legal issues and court rulings.

“Is there anything the Senate or Congress can do if a nominee says one thing seated at that table and does something exactly the opposite once they walk across the street?” he asked Sotomayor Wednesday during Day 3 of her confirmation hearings as she seeks to become the first Hispanic to sit on the high court.

I’ll bet there are plenty of Pennsylvania voters who want to know the same thing about Senators who switch parties. Perhaps the first and best opportunity to protect the interests of your constituency is to worry more about keeping your own promises instead of fretting about others keeping theirs.