Daniel Henninger has written an insightful opinion piece in today's Wall Street Journal  "Trump Is Killing Cruz: Ted Cruz had  plausible election strategy until Donald Trump stole it."
You might be able to link to the entire article HERE, but it could require an online subscription. If so, I highly recommend getting one. I read the Wall Street Journal, at least the Opinion Page every day. Well thought out, well reasoned articles, not the usual mud slinging, scarcely nuanced hysteria of some other publications.
Henninger made this excellent point that many people don't really understand:

Donald Trump is properly understood as running an independent candidacy from inside the formal structure of the Republican Party, as Mike Bloomberg did to run for mayor of New York City. Nothing remotely resembling a political party is associated with Mr. Trump. 

That's it. Trump is not a republican. He is not a conservative. He is NOT supported by the party. Who his supporters are is a mystery. But I think we can say with certainty that they are not individuals who truly understand or embrace conservatism. There may also be a number of people who really don't pay much attention to politics or political ideas, but are just taken in by the hoopla. And then there are some conservatives in the media...I don't know. Are they infatuated with him? Does his antipathy toward immigrants fuel a certain ugly animosity within them. I don't know. But what I do know is that he does not, in any way, shape, or form, represent republicanism.

Another good point:

The Cruz camp might argue that it has as much chance as Marco Rubio in a one-on-one contest against the Trump 33%. It’s far from clear, though, that the Rubio-Bush-Kasich vote would default to Sen. Cruz. The Cruz media-support operation for years has ridiculed vast swaths of the Republican Party, including lifelong Reagan conservatives, as the abhorrent “mainstream” or the “donor class.”

The media (and especially Trump supporters) keep saying that other candidates' dropping out of the race will be split among those remaining. I agree with Henninger. They are more likely to go to Rubio or, and this is scary, to Trump. Bush and Kasich are very different candidates than Cruz. 

This is the strangest election I can remember. (Sorry about the inconsistent line spacing. Couldn't get it to work.)