Sen. Ted Cruz talks to the media outside of his Senate office on Capitol Hill in Washington, U.S. Thomson Reuters Donald Trump suggested Ted Cruz's father had conspired to kill John F. Kennedy.

He threatened to "spill the beans" on Cruz's wife, Heidi.

He sent a tweet suggesting Heidi was ugly, especially compared to Trump's third wife who, like Trump's first wife, was a model.

He argued Cruz was ineligible to be president on account of his birth in Canada, and questioned his religious faith, noting, "not too many Evangelicals come out of Cuba, OK?"

When the National Enquirer alleged that Cruz had had five extramarital affairs, Trump issued a written statement saying he had "no idea" whether the Enquirer story was true, then adding "they were right about O.J. Simpson, John Edwards, and many others."

After all this, Ted Cruz endorsed Donald Trump for president.

What a cuck.

Back in July, when Cruz took the stage at the Republican National Convention and pointedly refused to endorse Trump, I puzzled over Cruz's choice, which struck me as politically disadvantageous and therefore not in line with Cruz's reputation as a man who would say or do anything to become president.

I wrote:

"My first assumption about politicians, and especially about Ted Cruz, is that they act in their own cynical interest. But it is also possible that Cruz simply saw an opportunity to take revenge on Trump, and he took it."

As we now know, I was wrong. Crapping all over Ted Cruz's immediate family turns out not to be a hard limit for Ted Cruz.

The only explanation left is that Cruz thought refusing to endorse Trump was in his political interest, and now he has changed his mind. But if Cruz is a craven and soulless politician just trying to say whatever will help him advance, he is not even very good at it.

In four years, Ted Cruz will be remembered as the guy who said Trump was "terrific" and "speaks the truth," and who then said he was "utterly amoral" and a "pathological liar," who knifed him at the back at the time when doing so did the most to harm the party's chances, and who then came back and endorsed him at the last minute, all without ever getting an apology for Trump's abuse of his family.

This does not seem like a track record that is likely to please either Trump's fans or his detractors.

Of course, Cruz can say he extracted some promises from Trump, including a written statement promising only to nominate Supreme Court justices from a pre-determined list of 21 vetted conservatives. Such a promise would seem valuable unless, of course, you believe Trump to be "utterly amoral" and a "pathological liar."

Cruz should have listened to my advice from some months ago: Donald Trump may beat you, but he can only take away your dignity if you let him or if you are Jeb Bush.

This endorsement will not help Ted Cruz become president. But it has revealed him to be a ridiculous, unprincipled, undignified man who does not even care if another man calls his father a murderer and his wife ugly.