The fact that his district re-elected him after Abscam demonstrates that there is nothing he could do, no matter how obscenely immoral, illegal, or stupid, that would result in his electoral defeat.
ABSCAM was barely mentioned in the latest campaign that got Murtha reelected. The newspaper in my hometown didn't mention it; the Pittsburgh t.v. stations didn't mention it. I doubt the voters in Murtha's district even know much about it. Diana Irey tried to run against him, but she didn't have enough money or clout to beat him. Republicans need to get an experienced, savvy, clean politician to run against him who's willing to shovel some dirt. Murtha can be beaten.
Yes, there is ONE thing he could do to make him unelectable even at this late date - he could change parties!