Texas Gov. Greg Abbott had a hard time naming an example of Texas Sen. Ted Cruz winning enough votes to pass something through the Senate.

Abbott endorsed the primary candidate earlier this week, calling him "a leader we can trust to restore our values and move this country forward." And in Thursday's debate, Cruz made the case that he should win the nomination for president because he is the only primary candidate who will ensure that "principled constitutionalist" justices are nominated to the Supreme Court.

In an MSNBC interview with Chris Matthews following the debate, Abbott struggled to defend his favored candidate. Matthews pointed out that as president, Cruz would need to get 60 votes to confirm a nominee -- and that he has shown little ability to do that during his time in the Senate.

"He's proven he can do it in the past. He'll do it again as president," Abbott said.

"What was the bill that got 60 votes in the Senate he advocated?" Matthews asked.

Abbott offered Cruz's ability to assemble "a nationwide coalition to support the Heller decision," referring to the Supreme Court's 2008 decision on Second Amendment rights.

"That was a Supreme Court decision!" Matthews said, before asking again for a legislative measure that Cruz has been able to pass.

Abbott again could not mention one, but said Cruz had the ability to do so.

"We do not want someone as president who will not appoint true conservatives to the United States Supreme Court," he said.