The judicial branch of the U.S. government is usually taken for granted. It doesn't command the hype and bloviating that the legislative and executive branches demand, especially in this day and age. The Supreme Court exists in a shroud of mystery, their discussions and arguments sealed airtight in their cozy Washington chamber. We don't think much of it, except when the judiciary season ends every late June and any political wonk worth their salt is scrutinizing the court's latest round of decisions.
For a Supreme Court that supposedly leans 5-4 in favor of conservatives, this year's round of decisions was an unexpected boost for a decidedly liberal president. Any conservative's hope of a lame duck presidency was quashed: the president's ambitious overhaul of our nation's health care system --er, "Obamacare"-- was kept intact in a narrow vote, and another slim decision legalized same-sex marriage in all 50 states. The impact of Obamacare still remains to be seen, and kinks clearly still need to be worked out, but the opposition has been forced to surrender.
As for Obergefell v. Hodges, the president might attempt to take credit but this was a populist court decision. Barack Obama's legacy will be filled with milestones in social progress (mostly for LGBTQ rights) but the fight for gay marriage first gained momentum about ten years ago, when the president was still a freshman U.S. senator. He championed the cause, albeit belatedly, but he never led the fight. Like many Americans, President Obama will have to sit down, kick back, and be amused the sheer novelty of two men getting married in deep-red locales like Mississippi and Arizona.