As oral arguments were beginning Tuesday in the first of two same-sex marriage cases inside the Supreme Court, the steps in front of the court were filled with throngs of what looked to be mostly gay-marriage supporters, spilling out in front of the building and to the other side of the street.
About a half hour earlier, a parade of traditional-marriage supporters had arrived, later headed to a rally on the National Mall.
When advocates for gay marriage talk about it, they usually focus on the struggle for equality and civil rights.
But how the Supreme Court decides the Defense of Marriage Act case being argued this week could possibly have big implications in another arena — the money same-sex couples owe the Internal Revenue Service.
The case that could throw out a law that defines marriage as between a man and woman started with a tax bill.
Outside the Supreme Court, lines began forming nearly a week ago. By Monday, the line had snaked down the court steps and to the corner, with people braving freezing temperatures and snow in anticipation of the historic arguments on same-sex marriage on Tuesday and Wednesday.
The justices are first hearing a constitutional challenge to California's ban on same-sex marriage. A second day is devoted to the federal Defense of Marriage Act, which denies federal benefits to same-sex couples married in the nine states where such unions are legal.