The plurality of Americans said they support same-sex marriage, according to a new poll.

The poll, released by POLITICO and George Washington University, showed that, out of 1,000 likely voters, 40% of respondents said they support marriage equality. 30% said they supported civil unions and 24% said they didn't think same-sex couples should be able to enter any type of legal union.

Even more telling, perhaps, is how many people--1 in 5--have changed their minds on the issue. This poll lends support to a growing trend that people are evolving on gay rights.

Another important finding is the discrepancy between young and older voters which it comes to the rights of same-sex couples. 63 percent of 18-to-29-year-olds backed same-sex marriage, while only 36 percent of voters from 30-59 said they supported it. Only 30% of seniors said they thought LGBT couples should be able to marry.

For many gay couples, marriage is finally becoming a reality. Today is the first day same-sex couples can get married in Washington, where citizens voted to legalize same-sex marriage in November. In two other states, Maryland and Maine, voters also legalized same-sex marriage. In Minnesota, voters rejected a ban on marriage equality.

Conservative columnist George Will said on Sunday opponents of same-sex marriage are "quite literally" dying.

Last week, the Supreme Court announced it would rule on Defense of Marriage Act and Proposition 8--the federal and California bans on same-sex marriage. Those rulings are expected in June. If DOMA is overturned, it would open the door to nationwide marriage equality. It would also mean that couples who marry in one state would be able to keep their rights in another.