In 1967, the Supreme Court of the United States invalidated laws banning interracial marriage in Loving v. Virginia. In doing so, the Court under Chief Justice Earl Warren demonstrated that it was ahead of the curve of public opinion. When the current Supreme Court hears arguments on two gay marriage cases beginning on Tuesday, the opposite may occur.

Support for gay marriage has never been higher than it is now — indeed, it has regularly increased over time, and opposition has faded.

(Over the weekend, some conservative gay marriage opponents argued that the polling on the topic was biased; one, Gary Bauer, even used the word "skewed." There's little indication that it doesn't accurately reflect opinion, Bauer's wishes notwithstanding. See our previous analysis of why polling may not match electoral politics.)

Polling on interracial marriage has followed a similar trend — albeit over a longer time period, and dropping from much stronger opposition.

(In both charts, data is from Gallup. Note that there can be significant gaps between polling periods.)

It's interesting to consider how those trends have compared over the decades. Support for gay marriage has trailed support for interracial marriage by about 30-40 points over time.

More relevant is how interracial marriage polled at the time of the Loving decision. In Gallup's first poll on the topic after it came down, conducted in June 1968, the public opposed the practice by a margin of 73 percent to 20. It wasn't until the 1980s that a majority of Americans supported interracial marriage.

The Court that decided Loving was one of the most liberal of the 20th century. The Court that will rule on California's Prop 8 and the Defense of Marriage Act is one of the most conservative. Talking Points Memo's David Kurtz posted this chart earlier today, tracking the ideological rankings of the Supreme Court over the past few decades.

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According to the data, the Court under Roberts right now is the most conservative it has been in 30 years.

That doesn't match public perception. A poll conducted by Pew Research indicates that 40 percent of Americans think the Court is balanced, though conservatives largely think it's liberal and liberals largely consider it conservative. (It's worth noting that TPM is a liberal media outlet.)

In other words, Americans, who largely support legalization of gay marriage, could be surprised by a more conservative ruling by the Roberts Court.

It seems likely that the trend toward acceptance of gay marriage will continue, as it did with interracial unions. But there will be holdouts. The map below shows those senators that have expressed support for gay marriage, a reflection of public opinion in the state. If the Court decides against overturning gay marriage restrictions, leaving decision-making to the states, it's likely that the last to ratify the practice will be some of those that were the last to embrace interracial marriage as well.

The Supreme Court was created specifically to operate outside the realm of public opinion. That's why it has the ability to override Congressional action and why Justices are appointed for life. It also means that there's no guarantee what it does will conform to what people want to see happen. In 1967, that reflected on the Court in one way. Bucking opinion this year would likely mean another reaction entirely.

(Pictured above: People hoping to witness the Supreme Court's gay marriage arguments waited in the snow on Monday.)