We are not voting for a saint, we are voting for the politician who will challenge the guy who is fully intent upon destroying this country. I want someone nominated who can take him out (politically speaking, of course), not some hyper-moral milquetoast who will lose. We tried that route with Carter after the mess of Watergate and associated scandals - how'd that work out for us? Seems to me that we're STILL dealing with the consequences of people in 1976 not voting with their heads, but with their hearts - Iran comes to mind.
The Perfect is the enemy of the Good.
That said, I certainly feel more comfortable that Newt has had enough humility to publicly state, on more than one occasion, that he did wrong, was sorry, and was walking the correct path now. Remember, we humans are purposely designed to be imperfect - our job is to improve ourselves, not to be perfect since that is impossible.
Christians are not without sin. There is always redemption and forgiveness though not always reconciliation.