"After many months of careful consideration, of prayer and searching my own conscience, I have decided that on Election Day, I will vote for the Republican nominee, Donald Trump,"
Cruz wrote in a Facebook post.
"A year ago, I pledged to endorse the Republican nominee, and I am honoring that commitment. And if you don't want to see a Hillary Clinton presidency, I encourage you to vote for him."
"I am greatly honored by the endorsement of Senator Cruz," Trump said in a statement obtained by CNN. "We have fought the battle and he was a tough and brilliant opponent. I look forward to working with him for many years to come in order to make America great again."
The move -- three days before Trump's critical first debate with Clinton -- comes as the Trump and Cruz camps have moved closer in recent weeks.
Trump's vice presidential nominee Mike Pence played a key role in bringing Cruz into the fold. Pence and Cruz traded multiple messages, then spoke at length once on the phone and again in person, when Pence visited Capitol Hill a few weeks ago, a source close to Pence said.
Trump has hired key Cruz allies such as Kellyanne Conway as his campaign manager, and Jason Miller as a spokesman.
Wednesday, Trump's campaign expressed support for a Cruz-backed, Internet-related proposal in government funding talks in the Senate.
Friday, Trump released a new
list of conservative judges likely to appeal to the former Supreme Court clerk -- including perhaps Cruz's closest friend in Congress, Utah Sen. Mike Lee.
Cruz cited Trump's pledges on the judiciary in his Facebook post. "We know, without a doubt, that every Clinton appointee would be a left-wing ideologue. Trump, in contrast, has promised to appoint justices 'in the mold of (the late Antonin) Scalia,' Cruz wrote. "For some time, I have been seeking greater specificity on this issue, and today the Trump campaign provided that, releasing a very strong list of potential Supreme Court nominees — including Sen. Mike Lee, who would make an extraordinary justice — and making an explicit commitment to nominate only from that list."
A Cruz endorsement could be the last pillar to helping Trump shore up the support of conservatives who have remained reticent about supporting his campaign.
Trump has already gotten most Republicans and conservatives on board with his campaign -- largely by reassuring them on the Supreme Court and on issues like the Second Amendment and abortion. But Cruz's principled opposition to offering his support has given some conservatives high-profile cover.
Just as Cruz's refusal to endorse Trump at the RNC fueled Democrats' efforts to paint Trump as divisive even within his own party, Cruz's endorsement will help undermine that narrative -- suggesting to conservatives unsure about Trump that perhaps the brash billionaire has changed, and can be trusted to bring conservative change to Washington.
'Lyin' Ted' and 'utterly amoral'
The move marks a dramatic turnaround from the personal insults Cruz and Trump traded during the previous year.
The two men clashed repeatedly during the primaries, as Trump taunted the senator with the nickname "Lyin' Ted," suggested Cruz wasn't eligible to be president due to his Canadian birthplace, and even speculated that Cruz's father was involved in the JFK assassination. Trump also said Cruz should "be careful" or he would "
spill the beans on your wife," and retweeted an unflattering picture of Heidi Cruz. Those tweets have not been deleted from Trump's account.
