Loyal staffers and longtime fans of Sen. Ted Cruz (R-Texas) were shocked and betrayed Friday afternoon, when Cruz endorsed Republican presidential nominee Donald Trump.

“Profoundly sad day for me,” conservative news host Glenn Beck wrote in a rambling post on Facebook. “Disappointment does not begin to describe my feelings. Maybe it is time to go to the mountains for a while.”

Cruz’s former campaign spokesman, Rick Tyler, told NBC News he was “mourning.”

Cruz's former comms guy, @rickwtyler, to me just now: "It's mourning in America for conservatives. We lost our leader today." — Hallie Jackson (@HallieJackson) September 23, 2016

Former Cruz campaign strategist Jason Johnson responded to news of the endorsement by sending a photo of himself with his hand over his face, according to Politico.

Explaining why he endorsed Trump, Cruz said that despite “areas of significant disagreement with our nominee,” he had promised to support the eventual GOP standard bearer. “By any measure, Hillary Clinton is wholly unacceptable,” he said.

The endorsement represented a startling about-face for Cruz, who, up until Friday, was a prominent anti-Trump Republican in Congress. The animosity between the two men went beyond politics. Trump insulted Cruz’s wife with a crude tweet during the GOP primary, and later suggested that Cruz’s father was an associate of the man who killed President John F. Kennedy.

Editor’s note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims — 1.6 billion members of an entire religion — from entering the U.S.