Former Congressman Barney Frank has applauded Texas Senator Ted Cruz for “evolving” on gay marriage.

Appearing on CNBC's Squawk Box, Cruz, a Republican, reiterated his opposition to marriage equality but added that states should be free to legalize such unions. However, he also criticized recent Supreme Court decisions that paved the way for marriage equality in 16 states, 3 of which have yet to comply with appellate court decisions.

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“I support the Constitution, letting each state decide each marriage law consistent with the values of their citizens,” Cruz said. “If the citizens of California decide they want to allow gay marriage, that's a decision for them.”

Frank, who appeared on the program after Cruz, described Cruz's comments as an “evolution” in how such unions are viewed in the United States.

“Ted Cruz is one of the most conservative people in American politics,” said Frank, who is gay. “He just made a very important statement that you quoted, that you ran on the air, which he said if a state wants to have same-sex marriage, that's okay. So even Ted Cruz's position, as I said he's the leader of the right in America, he represents an evolution in favor of allowing same-sex marriage.”

“It's even more vindication that the country is moving when someone on the right takes that position,” Frank added.