The U.S. Supreme Court will decide this term if same-sex couples have the right to marry nationwide, the judicial body announce Friday, a move welcomed by advocates of marriage such as the National Organization of Marriage.

"It is time for the 50 million Americans who stood for marriage in 30 states to have their day in court," said Brian Brown, president of the National Organization for Marriage.

Brown referred to the 30 states that defined marriage as between one man and one woman via popular vote.

Until the 6th Circuit Court of Appeals upheld traditional marriage amendments in four states in November 2014, similar amendments in other states had a string of defeats at the federal court level.

When five such cases were appealed to the Supreme Court in October, the Court had declined to review them.

Traditional marriage advocates were stung and aggrieved that the court would not take up the matter. Two leading bishops on marriage called the refusal "extremely disappointing and surprising."

Now, however, the court will hear arguments as to whether, under the 14th Amendment, states must issue marriage licenses to same-sex couples or recognize same-sex marriages conducted in other states.

"We are very pleased that the Supreme Court has chosen to review the 6th Circuit's ruling that found in favor of voters' right to define marriage as the union of one man and one woman," Brown responded to the decision.

"We will be watching this case closely and anticipate an eventual victory for the democratic process, religious liberty, and the cherished institution of marriage which forms the very bedrock of our society."

The 6th Circuit Court upheld amendments in Michigan, Ohio, Kentucky, and Tennessee. In the majority opinion issued by Judge Jeffrey Sutton, the judges stated that the question of marriage should be left up to the states and that the right of same-sex couples to marry is not in the Constitution.

"It is not society's laws or for that matter any one religion's laws, but nature's laws (that men and women complement each other biologically), that created the policy imperative," the judges upheld the marriage amendments.

The judges did leave the door open for change, but through political processes over judicial ones.

"Better in this instance, we think, to allow change through the customary political processes, in which the people, gay and straight alike, become the heroes of their own stories by meeting each other not as adversaries in a court system but as fellow citizens seeking to resolve a new social issue in a fair-minded way," the opinion concluded.

The oral arguments are expected to take place in late April, according to SCOTUSBlog.