By BARBARA LEONARD 

WASHINGTON (CN) – The U.S. Supreme Court agreed Friday to hold a hearing for four states that do not want to recognize same-sex marriages or grant licenses to such couples.

Though the justices broke gay-rights ground in June 2013 with United States v. Windsor, that case dealt only with a federal law that the court found was unconstitutional for defining marriage as the union of one man and one woman.

Many courts have since used that case as precedent for overturning state bans against same-sex marriage, and the latest crop of challenges concern whether these states violate the equal-protection rights of same-sex couples.

In a brief order consolidating four cases for oral argument, the Supreme Court agreed to answer two questions:

“1) Does the Fourteenth Amendment require a state to license a marriage between two people of the same sex? 2) Does the Fourteenth Amendment require a state to recognize a marriage between two people of the same sex when their marriage was lawfully licensed and performed out-of-state?”

Briefs from the petitioners are due on Feb. 27, and the respondents must file their briefs by March 27. Replies are then due on April 17.

The state laws at issue in the cases that the court took up belong to Ohio, Tennessee, Michigan and Kentucky.

In early November, a divided three-judge panel of the 6th Circuit reversed rulings by federal judges in those states that struck down their bans on same-sex marriage.     

News of the Supreme Court’s grant led Attorney General Eric Holder to emphasize his office’s commitment “to ensuring that the benefits of marriage are available as broadly as possible.”

“As such, we expect to file a ‘friend of the court’ brief in these cases that will urge the Supreme Court to make marriage equality a reality for all Americans,” Holder added. “It is time for our nation to take another critical step forward to ensure the fundamental equality of all Americans – no matter who they are, where they come from, or whom they love.”

Judith Schaeffer, the vice president of the Constitutional Accountability Center, called the Friday grant of certiorari a “key milestone” on the road to marriage equality. 

Three dozen states have made marriage equality a reality, but the 14th Amendment “prohibits all 50 states from depriving gay men and lesbians of the fundamental right to marry,” Schaeffer added.

“I am confident that the Court will get the Constitution ‘right’ when it decides these new cases, and that same-sex couples will no longer have to live in a balkanized America,” she continued.