Republican presidential candidate Mike Huckabee has warned that nationwide marriage equality threatens to “criminalize Christianity.”

The nation's highest court heard arguments in a case challenging bans in Ohio, Tennessee, Michigan and Kentucky on April 28. A ruling, which could lead to nationwide marriage equality, is expected in the next week.

In a letter to socially conservative religious leaders, Huckabee said that a ruling striking down state bans would be just as “backwards” and “broken” as those which “rationalized the destruction of human life, defined African-Americans as property and justified Japanese-American internment camps.”

“I refuse to sit silently as politically driven interest groups threaten the foundation of religious liberty, criminalize Christianity, and demand that Americans abandon Biblical principles of natural marriage,” Huckabee wrote. “I will fight to defend religious liberty at all costs.”

(Related: Mike Huckabee stands by “commonsense” transgender comments.)

He reiterated that he would ignore such a ruling.

“I also refuse to surrender to the false god of judicial supremacy, which would allow black-robed and unelected judges the power to make law and enforce it, which upends the separation of powers so very central to our Constitution,” Huckabee said. “Too much power concentrated in the courts is a threat to our Republic. I will fight judicial tyranny and return power to the people.”

(Related: Albert Mohler admits there's no threat to pastors who refuse to marry gay couples.)