In fact, exit polls now show a majority of both groups now favor gay marriage.
Maine, Maryland and Washington state all passed new gay marriage laws on Tuesday, while voters in Minnesota defeated a ban.
In some ways, the pro-gay marriage votes were a long time coming, with polls showing more and more Americans moving in support of gay marriage in recent years. But the fact that voters in multiple states signed off on gay marriage all at once on Tuesday suggests a significant leap forward, in addition to the incremental progress.
And while the usual suspects continue to favor gay marriage -- young people and non-religious people -- exit polls show the most important shifts in support among two key communities: African Americans and Hispanics.
Black voters, in particular, have been slow to embrace gay marriage, even as the vast majority vote Democratic and the rest of the party has embraced gay marriage. On Tuesday, though, they played a major role in passing Maryland's new gay marriage law.
Maryland is heavily Democratic, which made it a likely candidate to be one of the first states to vote for gay marriage. But the state is also heavily African-American (29 percent) and has a significant Latino population (8 percent), which made passage something less than certain.
When California voted for a gay marriage ban in 2008, 70 percent of African Americans voted for it, and when North Carolina overwhelmingly passed a similar measure earlier this year, many cited the black vote as a big reason. (Shortly after the ban passed in North Carolina, President Obama came out in favor of gay marriage.)
On Tuesday in Maryland, though, 46 percent of African Americans supported gay marriage. And according to national exit polls, 52 percent of both black and Latino voters who turned out Tuesday said they support gay marriage in their states.
(The largest shift came from black women, of which 59 percent now support gay marriage, compared to 42 percent of black men -- a huge gender gap.)
That's a big turnaround from recent years. In 2008 and 2009, a Pew Research Center survey showed just 28 percent of African Americans and 39 percent of Latinos backed gay marriage. And by 2010, support in those communities was rising slower than it was among whites.
The exit polls suggest both groups have now moved in large numbers toward supporting gay marriage. Their shifts may not be bigger than other demographics, but the fact that they are shifting at all (after sticking to their opposition) is what's really significant here.
And given their affinity for President Obama -- 93 percent of African Americans and 71 percent of Latinos voted for the president -- it's not unreasonable to think that his support had an impact.
That said, the other three states (besides Maryland) that voted in favor of gay marriage Tuesday are among the whitest states in the country, with Maine being the whitest and Minnesota being 83 percent white.
That's not surprising, as support has also increased among many other demographics, including Republicans and older people.
But the fact is that the states that are the most Democratic -- and thus the likeliest candidates to pass gay marriage laws -- tend to be more diverse (California, New York, New Jersey, Illinois, etc.). And if African Americans and Latinos are as onboard with gay marriage as the exit polls suggest, the four states that voted in favor of gay marriage on Tuesday might be the first of many.