To be fair, in D.C.'s case, it's not merely an issue of liberalism, it's an issue of corruption as well. The D.C. government is notoriously corrupt, and even the most outrageously criminal behavior isn't enough to put an end to one's political career there (just look at Marion Barry). However, having said that, the corruption is at least partly due to the city government being so utterly dominated by liberal Democrats. Not that corruption is exclusive to Democrats or liberals by any means, but when one side, either side, comes to have pretty much a lock on the government, and the other is frozen almost completely out, corruption is almost sure to become more of a problem.