I've been contending for some time that the subject of same-sex marriage is headed for the Supreme Court and that how it turns out depends solely on the opinion of one person -- Justice Anthony Kennedy. This interesting article from the Witherspoon Institute tries, without much success, to figure out where Kennedy might stand on the issue:
Kennedy’s past opinions on related questions seem to indicate his openness to the constitutionalization of same-sex marriage, but the evidence is nevertheless equivocal. Kennedy authored Lawrence v. Texas, in which the Court struck down Texas’s law against homosexual sodomy, and in that opinion Kennedy permitted himself to wax somewhat indignant about the supposed irrationality of moral disapproval of such conduct. On the other hand, he also used that opinion to assure the nation, in the Court’s name, that the issues in that case had nothing to do with the question of same-sex marriage. As a result, Kennedy might not be so favorably disposed to a constitutional claim for same-sex marriage, since the advance of that cause has been for the last decade linked to the work of state courts that turned Lawrence’s reasoning precisely to the end that Kennedy and the Court disclaimed.
The president always has a claim on the title of "most powerful person in America," and a good argument can be made that Barack Obama deserved it for his first two years in office. But since the House went to Republicans in 2010, somewhat checking Obama's influence, I think we have to give the title to Kennedy. Given the court's 4-4 liberal-conservative split, he can move this country in whatever direction he wants based on whatever whim he cares to indulge, and he never has to face the voters.