Rudy is entitled ping.
Rudy is entitled to be indicted - ping :-)
So far, Fred looks fairly clean (apart from the fact that he took more than $5000 to push pro-abortion legislation as a lobbyist--an ethical breach of a different kind).
But Mitt's ethics background is spotless. In fact, Mitt is a hard-headed businessman, a notorious tightwad. He's never shown the slightest tendency to want to gorge himself at the trough of special interests and hidden slush funds. He's wealthy by his own effort but not greedy for filthy lucre.
The severely ethically-challenged and corrupt Hillary will likely be the Democratic candidate. Only Mitt and Fred can speak boldly to her many ethical failures without sounding like hypocrites.