Texas Senator Ted Cruz, who is frequently mentioned as a possible 2016 presidential candidate, has pledged to introduce a constitutional amendment defining marriage as a heterosexual union.

Cruz, a Republican, released a statement in response to the Supreme Court's refusal to review appeals in cases challenging gay marriage bans in five states, effectively legalizing marriage equality in 11 states.

A furious Cruz called the court's decision to let lower court rulings stand “both tragic and indefensible.”

“By refusing to rule if the States can define marriage, the Supreme Court is abdicating its duty to uphold the Constitution. The fact that the Supreme Court Justices, without providing any explanation whatsoever, have permitted lower courts to strike down so many state marriage laws is astonishing.”

“This is judicial activism at its worst.”

“Marriage is a question for the States. That is why I have introduced legislation, S. 2024, to protect the authority of state legislatures to define marriage,” he said, a reference to the State Marriage Defense Act of 2014, which has 10 Republican co-sponsors.

“And that is why, when Congress returns to session, I will be introducing a constitutional amendment to prevent the federal government or the courts from attacking or striking down state marriage bans.”

He concluded: “Traditional marriage is an institution whose integrity and vitality are critical to the health of any society. We should remain faithful to our moral heritage and never hesitate to defend it.”