Ted Cruz defended not endorsing Donald Trump for president as he spoke Thursday morning in front of a lively group of Republican delegates from Texas, explaining that it was personal for him. "It is not a game, it is not politics" when someone launches a personal attack on one's family, he said. Cruz was indirectly referring to Trump's negative comments about Cruz's wife and father during a contentious Republican primary season.

"I am not in the habit of supporting people who attack my wife and who attack my father," he declared defiantly in front of a crowd that included many who wanted Cruz to uphold his pledge to support the Republican Party's presidential nominee.

Cruz said he Trump never asked for his endorsement and that he told Trump hours in advance of the speech that he would not be offering a formal endorsement, prompting a member of the audience to yell, "Why not?"

Cruz insisted he would not utter a single negative word about Trump and asked conservatives not to stay home and to go out and vote "for candidates that you trust to defend our freedom and to faithful to the constitution." But when the audience heard that they began booing, a response that Cruz called "a little bit troubling."

He said he took that to mean that the audience didn't believe that Trump was a proponent of the Constitution.

While his explanation wasn't completely accepted by all in attendance, the Texas senator did quell some other concerns about Election Day: "I can tell you, I’m not voting for Hillary," he declared.

This is a developing story.