Seeing a candidate "prove his conservative cred" is just not on the minds of most Republican voters this election cycle. They're more concerned about illegal immigration and bad trade deals, and the negative impact those have had on the US economy and living standards for the past few decades.
By the way, what is the proper conservative position on illegal immigration and trade deals in general? And what conservative would you say has "proved his or her conservative cred" on those issues?
“And what conservative would you say has “proved his or her conservative cred” on those issues?”
I was asking the same question you are asking. Only it was specifically about Trump.
The question came because a Cruz detractor wanted to know “What has Cruz done?” I thought it was fair to ask “What has Trump done”.