My layman's opinion on the Cruz candidacy.
He has absolutely no chance whatsoever of winning a general election. The left hates him and he'd get no crossover. The GOPe hates him and many of them would vote for Hillary.
But the GOPe is desperate to get Trump off the ticket. They give all kinds of excuses why, but the real reason is because it would upset the grand deal they have with the dems to expand gov't in both domestic policy and wars abroad. All their power and glory would be at risk.
The GOPe figures that if it put one of their own on the ticket at a contested convention, all the Trump people might bolt, not vote in the general, and it would put their own congressional seats at risk.
So, they'll push for Cruz and let him be the nominee, knowing that he has no chance, which is fine with them. This accomplishes many things for the GOPe.
1. They figure most conservatives will still go to the polls, helping them retain their congressional seats.
2. They figure Cruz will lose to Hillary, which they want because it will keep the grand deal between dems and repuds to expand social programs and wars in place.
3. They can then proclaim that conservatives can't win the general and we need to place a mccain or romney on the ticket next time.
The GOPe knows it can't get it all, but this way they can get most all of what they want.
Let's face it. Why else would GOPe's like Romney back Cruz? Nobody thinks the GOPe actually want Cruz to win the general, do they?