From Today's Wall Street Journal:

The most satisfying outcome across all parties and ideologies was arguably Democratic Congressman Joe Sestak's comfortable victory over Democrat turned Republican turned Democrat Arlen Specter in the Pennsylvania Senate primary. In defeating the 80-year-old Mr. Specter, voters showed there is at least some limit to partisan opportunism and thus committed an act of political hygiene.

Mr. Specter fled the GOP last year when it became clear he would lose a Republican primary to former Congressman Pat Toomey, and he promptly switched positions on everything from union "card check" to health care. Mr. Sestak ran by claiming to be the more authentic Democrat, despite President Obama's embrace of Mr. Specter, at least as long as the President needed him for the 60th health-care vote. In crunch time in the primary, the White House decided to sit this one out. One disloyal act is repaid in kind.