He stopped the 'it was just a joke' line to try a new excuse- it didn't work.
During Thursday night’s Republican presidential debate, presidential candidate Donald Trump tried to defend previous comments about how he would potentially nominate his pro-abortion sister to the Supreme Court.
Trump has faced criticism in some quarters from pro-life voters who point to a past interview he gave about his sister, who is a pro-abortion attorney.
As National Review reported in 2015:
Donald Trump told Mark Halperin yesterday that his sister, a federal judge, would be a “phenomenal” Supreme Court justice. He also said that “we will have to rule that out now, at least.”......
http://www.lifenews.com/2016/02/26/donald-trump-falsely-claims-justice-samuel-alito-supported-partial-birth-abortion-like-his-sister/