One of the anti-Trump tools is to take the claim the mantle of "conservative," whatever that means is up to the listener. No surprise that Erickson would not support Trump under any party, and I figure Trump will not ever get the support of a good fraction of both social conservatives and party faithful. stands to reason. The social cons think the president sets social policy; and the party faithful are protecting their gravy train, status quo. Change is generally uncomfortable.
Which is why Trump is winning the Christian vote. Most Christians are not electing a pastor and like when someone finally calls out the Islamic threat. Most Christians only want to be respected and not preached to.
Cruz really hurt himself in Iowa with many Christians.