WASHINGTON — On Friday, the Supreme Court announced that it will be deciding the question of same-sex couples' marriage rights this year.

Left unsaid, however, was the fact that the outcome is almost certain: nationwide marriage equality by July of this year.

Since the Supreme Court struck down the Defense of Marriage Act's ban on federal marriage recognition in 2013, the nation's lower courts have created significant momentum toward this moment.

But it is the Supreme Court's actions over the past 15 weeks, and the broad set of cases the court agreed on Friday to hear this spring, that makes the coming ruling practically preordained.

By issuing several orders in recent months allowing for more and more same-sex couples to be marrying in more and more states, the Supreme Court has made nationwide marriage equality a far less radical decision. It also has made it so that a decision upholding state marriage bans as constitutional would cause significant, difficult problems.

The Supreme Court has, in fact, played the key role in creating the national landscape that now exists: Same-sex couples are marrying in, at least parts of, 37 states and Washington, D.C.

On Oct. 5, 2014, that number was 19 states and D.C.

And though there have been no opinions explaining why the Supreme Court has done what it has done since then and though the decisions do not, technically, bind the court, there is at least a majority of the court comfortable creating this landscape, which would be difficult and extraordinarily painful to undo.

In that time, the Supreme Court's actions have directly or indirectly led to same-sex couples being allowed to marry in 14 of the additional states with same-sex couples marrying now.

The justices, on Oct. 6, 2014, denied five states' requests for the court to hear their cases and reverse the appeals court decisions that struck down marriage bans. That decision to deny those writs of certiorari meant same-sex couples began marrying in those states, as well as in six other states within those appeals court circuits.

Then, the Supreme Court refused to issue stays (or holds) of lower court rulings in Idaho and later Alaska while the states attempted to appeal the rulings. Those orders, which came with no reasoning, followed the decision of the 9th Circuit Court of Appeals to strike down Idaho and Nevada's bans. Because there already was an appeals court ruling in favor of marriage equality that applied to those states, the orders were seen as being similar to the court's Oct. 6 decision.

But then, on Dec. 19, 2014, the Supreme Court denied a stay during Florida's appeal of the federal marriage case challenging its ban. In Florida, unlike in any of the other states where the justices allowed same-sex couples to begin marrying, the appeals court for that circuit had not ruled on the issue.

This decision by a majority of the justices to allow same-sex couples to marry while appeals are ongoing — and before the Supreme Court has resolved the issue itself — means that a majority of the court is comfortable with that reality becoming the default.

More than that, the decision to allow same-sex couples to marry before the Supreme Court has decided the issue creates more legitimacy for an eventual decision striking down the bans by increasing the number of states where same-sex couples already can marry. At this point, a decision striking down such bans nationwide only changes the situation in 15 states. Before the justices started down this path on Oct. 6, 2014, it would have meant changing the law of more than 30 states.

Additionally though, and perhaps making the outcome of this spring's Supreme Court showdown even more certain, the Supreme Court would be opening up an unprecedented mess if it upheld the bans now as being constitutional.