Alex Wong/Getty Images Texas Sen. Ted Cruz delivers a speech on the third day of the Republican National Convention.
Most of Cruz's speech seemed well-received by the crowd at the Quicken Loans Arena in Cleveland, but once it became clear that the former 2016 presidential candidate would not endorse Trump, the crowd started booing.
Not only did Cruz neglect to endorse Trump, but he also told the audience to vote their conscience in November.
"To those listening, please, don't stay home in November," Cruz said. "Stand, and speak, and vote your conscience, vote for candidates up and down the ticket who you trust to defend our freedom and to be faithful to the Constitution."
Boos and a chant of "We want Trump!" rose up from the crowd.
Cruz paused, then said: "I appreciate the enthusiasm of the New York delegation."
He then completely lost the crowd. Some in the audience were booing, some were chanting, and many were shouting over him as he pushed ahead with his prepared remarks. The noise from the crowd almost completely drowned out what Cruz was saying at the end of his speech.
Trump himself appeared in the arena as Cruz was finishing speaking, and the senator exited the stage to more boos.
The moment everyone is talking about: @tedcruz booed off stage after he refused to endorse Trump. #RNCinCLE pic.twitter.com/83sBYZPrDl
- FOX Business (@FoxBusiness) July 21, 2016
After the speech, Cruz's wife Heidi was escorted out by security amid an angry crowd, according to CNN reporter Manu Raju.
Cruz stuck very closely to his prepared remarks, and much of his speech stuck very closely to the party's post-2012 "autopsy report" that analyzed where Republicans went wrong the year Mitt Romney lost the election. That report stated that the party must be more inclusive if it is to remain relevant.
Cruz said:
"Our party was founded to defeat slavery. Abraham Lincoln, the first Republican president, signed the Emancipation Proclamation. We passed the Civil Rights Act, and fought to eliminate Jim Crow laws. Those were fights for freedom, and so is this."
Earlier in the day, Cruz held a thank-you event at a restaurant in Cleveland for campaign volunteers. His speech there touched on similar themes, and many of his supporters in the crowd chanted "2020! 2020!" and booed as Trump's plane flew overhead.
Cruz, who came in second place in the delegate count but couldn't manage to stave off Trump in the primaries, is thought to be a likely contender for the Republican nomination in 2020 if Trump loses the White House this November.