Fredreka Schouten

USA TODAY

WASHINGTON — Two of Sen. Ted Cruz’s biggest financial backers on Saturday sharply criticized the Texas senator for not endorsing Republican presidential nominee Donald Trump during the Republican National Convention.

Hedge-fund billionaire Robert Mercer and his daughter, Rebekah, issued a rare public statement, slamming Cruz, who suggested during his convention appearance that Republicans “vote their conscience.”

In a statement, the Mercers said:

Last summer and again this year, Senator Ted Cruz pledged to support the candidacy of the nominee of the Republican Party whomever that nominee might be. We are profoundly disappointed that on Wednesday night he chose to disregard this pledge. The Democratic Party will soon choose as their nominee a candidate who would repeal both the First and Second Amendments of the Bill of Rights, a nominee who would remake the Supreme Court in her own image. We need "all hands on deck" to ensure that Mr. Trump prevails. Unfortunately, Senator Cruz has chosen to remain in his bunk below, a decision both regrettable and revealing.

Mercer, who co-founded Renaissance Technologies, donated $13 million to a super PAC supporting Cruz’s failed presidential bid. The Mercers now are helping fund a new super PAC to oppose Clinton, run by David Bossie, the head of the conservative advocacy group Citizens United.

Major GOP donor gives $2M to anti-Clinton PAC

The Mercer’s rebuke, first reported by The New York Times, could point to fundraising trouble for Cruz, who is up reelection in 2018 and could mount a second presidential bid in four years.

During an event Friday in Cleveland, Trump openly mused about setting up his own super PAC to oppose Cruz in 2018.