This may be what could really get under Trump’s skin:

Ted Cruz Calls Donald Trump’s Sister, a Judge, an ‘Extremist’

Senator Ted Cruz took aim on Monday at the judicial record of Donald J. Trump’s sister, calling her a “radical pro-abortion extremist” unfit for the Supreme Court.

Mr. Trump has said in the past that his sister, Maryanne Trump Barry, a senior judge on the United States Court of Appeals for the Third Circuit in Philadelphia would make an effective Supreme Court justice. On Sunday, he told ABC that he had only suggested it “jokingly.”

Speaking to reporters here on Monday, Mr. Cruz treated Ms. Barry’s prospective nomination as serious.

“Now, it’s good to stand with your sister,” he said. “But Donald’s sister was a Bill Clinton-appointed federal appellate judge who is a radical pro-abortion extremist.”

In fact, Ms. Barry was initially appointed to the bench by Ronald Reagan and promoted by Mr. Clinton.

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Ted really likes to deceive. No wonder Trump is beginning to zero in on him.