Ted Cruz explains Trump endorsement at Fort Worth event

Texas Sen. Ted Cruz spoke publicly for the first time Wednesday since his endorsement of Donald Trump and said he did it to prevent Hillary Clinton from winning.

"Although I have long had significant concerns with Donald, by any measure, Hillary Clinton would be an absolute disaster as president,” Cruz said during a visit to Tarrant County Republican headquarters.

Cruz was widely booed and dropped in favorability ratings after not endorsing Donald Trump during his speech at the Republican National Convention. During the primary battle, Trump made disparaging comments about wife Heidi Cruz and Cruz's father – accusing him of involvement in the JFK assassination.

“I am not in the habit of supporting people who attack my wife and attack my father,” Cruz said at a Texas GOP delegation breakfast back in July.

Cruz said he prayed and spoke with members of his family before deciding to endorse Trump last week.

"A year ago, I stood on stage and promised to support the Republican nominee, whoever that was, and I am honoring my word," Cruz said on Wednesday.

SMU political scientist Cal Jillson said Cruz was likely pressured to get on the Trump train.

“Major donors, but also other officials in Texas politics -- most clearly Lieutenant Governor Dan Patrick -- called on him to get back in line,” Jillson said.

Cruz is up for re-election as Texas senator in 2018.