CLEVELAND — Texas U.S. Sen. Ted Cruz and Ohio Gov. John Kasich yesterday stood firm in their refusal to back their party’s nominee in the general election as a tumultuous Republican National Convention wound down, roiled by internal feuds between the GOP runners-up and Donald Trump’s campaign.

Cruz, who won almost 8 million Republican votes and was habitually referred to as “Lyin’ Ted” by Trump, told his home state delegation that Trump’s attacks on his wife and father immediately nullified his pledge to support the party’s nominee.

“That pledge was not a blanket commitment that if you go and slander and attack Heidi, that I am going to nonetheless come like a servile puppy dog and say, ‘Thank you very much for maligning my wife and maligning my father,’ ” Cruz said. “The day the pledge was abrogated was the day this became personal.”

During the primary campaign, Trump at one point retweeted an unflattering photo of Cruz’s wife, Heidi, alongside his supermodel wife, Melania. His campaign was also suspected of spreading social media reports regarding a depressive episode Heidi Cruz had suffered years ago. And Trump suggested at one point Cruz’s father, Rafael, may have been involved in the assassination of President John F. Kennedy.

Cruz gave a prime-time address Wednesday night urging viewers to “vote your conscience” — a call that led to him being booed off the convention stage in an extraordinary display of the deep fissures the ugly primary left in the Republican Party.

Cruz defended his speech yesterday.

“If we can’t make the case to the American people that voting for our party’s nominee is consistent with voting your conscience and consistent with defending freedom and being faithful to the Constitution, then we are not going to win and we don’t deserve to win,” he said.

Meanwhile, Kasich — under intense heat for refusing to even appear at the convention in the state he governs — vowed to continue to “stand on principle.”

“I think you can all understand why I didn’t show up to speak at the convention, after what you saw last night,” Kasich told Ohio delegates, referencing the boos that greeted Cruz.

“There are a lot of people wondering, ‘What am I doing?’ ” Kasich told the crowd. “We want politicians to stand on principle and whenever they do, if it’s not the principles we like, we are not so much into them standing on principle.

“I can tell you when you stand on principles, sometimes you stand alone,” he added. “And that’s cool, because at the end of the day it’s just you and the mirror.”