I don't agree RP should now attack Romney. Keep the soft tone! Romney will keep making mistakes, he is unelectable. Ron Paul shouldn't expose himself too much now. Offense winning games, defense winning championships. Just let Romney further disqualify himself and the rest will happen automatically. Keep amassing delegates, this will be easier now for RP.
Santorum already should have 340 delegates. Projecting final 300 for Newt, requires us to have 500 RP delegates in Tampa to survive 1st ballot. One thing for sure: Texas is the key.
You can attack and be nice at the same time. Romney is unpredictable. What will we get in the White House, assuming he wins (IMO, he won't): the liberal/moderate Mitt or the conservative Mitt that he's claiming to be now? I think he already said last month that he would "tone it down" as soon as he clinches the nomination.
It's a valid concern, and I think it should be brought up.