Sign a law nationally legalizing SSM instead of forcing it through the courts.
The federal government does not have that authority, at least not directly.
Marriage is the purview of the states & it's the states that determine the requirements thereof, including who's eligible to enter into one as well as when & under what conditions a marriage can be annulled (divorce). This is why it's easier to get married &/or divorced in some states than others. Federal law & the Constitution ensure that states must recognize marriages made in other states; so, if you get married in Texas, all of the other states must recognize that marriage, but the federal government can't dictate marriage requirements to the states through legislation.
Meanwhile, the judiciary can (& obviously has) determined constitutional limitations on what states can do, & they've ruled that states can't deny marriage based on the sex of people getting married, as doing so would be in violation of the Constitution. That is something which the Courts can do but which federal legislation couldn't.
