Heck no.
If Walker and Rand can survive Cruz’s campaigning then they can survive anyone.
If they can’t Cruz deserves to be President and not them. It will be interesting to see if Cruz can manage a complex Presidential campaign.
So far, he seems to be doing pretty good.
My hope is they will team up. Pres / VP to catch all the conservative votes. I’m so afraid they will split the conservative vote and Bush will slide right in with all the moderate vote. Anxiously awaiting primaries.