In a historic and landmark vote, the state of Maine has legalized same-sex marriage by popular vote.

Maine joins Maryland in becoming one of only two states to legalize same-sex marriage at the ballot box. Maryland voters approved their measures tonight as well. As of 10 p.m. PT, a similar measure in Washington state was leading 52 percent to 48 percent.

“This is a landmark election for marriage equality and we will forever look back at this year as a critical turning point in the movement for full citizenship for LGBT people,” said HRC President Chad Griffin, in a statement released moments ago.

“Voters in Maine came to the common-sense conclusion that all people deserve the ability to make loving, lifelong commitments through marriage,” “We are thrilled for all Maine families and for the dedicated campaign that led this effort through to the end. As we celebrate victory tonight we know we have added momentum to ensure that this victory is soon felt in every corner of this country. Poll after poll shows a majority of Americans supporting marriage equality and the numbers continue to grow every single day. “Mainers United for Marriage ran a stellar campaign under the leadership of Matt McTighe and HRC has been proud to have been a part of this fight since the beginning.”

The HRC contributed more than $800,000 to advance marriage equality in Maine, sent 85,000 emails to supporters of marriage equality, recruited several hundred volunteers and sent staff to work on the campaign.

Same-sex couples will be able to begin marrying on, or about, December 6 at the earliest, although this date may change. The initiative goes into effect 30 days after the governor makes a “public proclamation of the result of the vote,” and within 10 days after the result has been determined.