There is no rule that there has to be a balance between progressives, liberals, and conservatives on the Supreme Court, and President Donald Trump could appoint a conservative who will vote to overrule past court decisions to replace retiring Justice Anthony Kennedy, Harvard Law Professor Emeritus Alan Dershowitz said Thursday.

"The framers of the Constitution intended the Supreme Court to be an elitist check and balance on the excesses of democracy as represented by the popular branches of government, the House of representatives, the Senate, the president," Dershowitz told Fox News' "Fox & Friends."

The key is whether Trump will appoint a justice who believes in the legal practice of "stare decisis," which means to let old past decisions stand, or to appoint a conservative who says he or she did not take "an oath to past precedents, but to my interpretation of the Constitution."

However, many decisions that have been applauded in recent years were those that overturned past decisions, such as on same-sex rights or school desegregation, said Dershowitz.

"Liberals applauded those decisions, but if Roe vs. Wade were overturned, liberals would be appalled by that decision," said Dershowitz.

The professor also discussed the behind-doors questioning of FBI agent Peter Strzok,saying that keeping his meeting with House members private did not allow Americans the ability to assess his credibility.

"You have to see him, see his facial expressions, how many times he turns to his lawyer, whether it looks like he's making up a story to satisfy the American public," said Dershowitz. "We have a right to see him. This hearing should be open. . . explaining what he meant by an insurance policy to prevent the election of a president is something the public has a right to see.