In Washington this week, the Supreme Court is hearing oral arguments in two cases challenging legal obstacles to marriage equality in the United States.

On Tuesday, the court heard arguments pertaining to the case Hollingsworth v. Perry, a challenge to the gay-marriage ban known as Proposition 8 that was passed by popular vote in California in 2008. Today, the court will hear arguments in the case United States v. Windsor, a challenge to the Defense of Marriage Act, the 1996 law by which the federal government legally recognizes only marriages between one man and one woman.

These cases represent an opportunity for the Supreme Court to advance the cause of marriage equality for gay couples. It is unclear how the court will rule and to what extent its ruling will change the national legal framework around marriage, but we believe that the court, when it hands down its decisions in a few months, should act broadly to strike down both Proposition 8 and the Defense of Marriage Act on the grounds that gay couples and straight couples should be treated identically under the law.

Though we do not believe that the rights of a minority group should ever be put to a majority vote, the change in public attitudes about gay marriage in recent years is undeniable. The country, thankfully, is a much different place than it was when the Defense of Marriage Act passed with bipartisan support under President Clinton in 1996. Much has changed even in the four and a half years since Proposition 8 passed in California.

In 1996, 68 percent of Americans opposed gay marriage and only 27 percent approved of it, according to Gallup. By 2008, 56 percent opposed and 40 percent approved. According to a CBS News poll released Tuesday morning, 53 percent of Americans now believe same-sex marriage should be legal; 38 percent believe it should be illegal.

The change in public opinion corresponds with an unprecedented embrace of marriage equality among America’s politicians. In the spring of last year, President Obama became the first sitting president to come out in favor of full marriage equality. Already this year, Hillary Rodham Clinton and Democratic senators such as Montana’s Jon Tester and Missouri’s Claire McCaskill have embraced same-sex marriage. Republican Sen. Rob Portman of Ohio, who was reportedly on Mitt Romney’s short list of running mates, announced that he has supported marriage equality since he learned that his son is gay.

The Supreme Court should heed changing public opinion as they decide the fate of these court cases and act to ensure that all couples are treated equally under the law. This, of course, means that couples, gay or straight, should have access to the same legal benefits of marriage; but it also means tearing down the rhetorical barriers that cordon off gay couples in “separate-but-equal” civil unions.

A marriage is a marriage; a civil union is an optical illusion.

The Daily Iowan Editorial Board encourages Iowa City residents to support the Supreme Court justices to strike down these unjust prohibitions and, in doing so, make the broad statement that under the American Constitution, everyone should be treated equally. It’s time for full marriage equality in the United States.