Overall, would have to agree with Paddy James. There are exceptions, of course. In the 1920s the corrupt mayor was Big Bill Thompson and the clean one was a Democrat. Thompson lost his last race to a corrupt Democrat, Anton Cermak, and it has been in the hands of corrupt Democrats ever since. In Atlantic City, the corrupt mayor was Enoch Johnson, another Republican. In New York City it was the other way around, with corrupt Democrats until Fiorello LaGuardia, who was an anti-crime Republican.

Individual cases of corruption aside, in terms of general policy, the Republicans are generally anti-union and strong on law and order, so less friendly to organized crime. If the Libertarians ever came to power it would be a different story. They would probably decriminalize all illegal drugs, legalize loan sharking (without the violence) and all forms of gambling and prostitution. However, they aren't too pro-union.