Not too hard for the Dems to do that, since DT already established the narrative for them to follow. DT is their dream candidate; "anti-immigrant, islamophobic" (Dem words, not mine) enough to be painted as an extreme bogeyman for their base, yet malleable (as Carter said) on healthcare, gay rights and Planned Parenthood.
I don’t agree with your assessment of Trump. But I will say that Cruz brought it upon himself with the “to the limit” campaign tactics in Iowa and now in SC. And I still have to ask, why isn’t Cruz going after Jeb? A Jeb threat is certainly a very big threat to the nation, whereas Trump will turn things around.