US Representative William Delahunt

Warchest: $1.2 million

Chance of running: Almost nil. “I’m not interested,” he said in an interview. “I chair oversight on foreign affairs and I’m on important committees. I wouldn’t want to give up that seniority.”

Pro: Has the money it would take, is savvy on foreign policy, and is popular in a district that would come out to vote in a special election.

Con: He has several powerful committee assignments and is also mentioned among possible Obama administration appointments, perhaps as an ambassador.