Gov. Martin O'Malley has pledged to sign the bill into law, which had been approved earlier this month by the Maryland House of Delegates.
"All children deserve the opportunity to live in a loving, caring, committed and stable home, protected equally under the law," O'Malley said after the 25-22 vote, taken less than two weeks after Washington state legislators voted to legalize same-sex marriage. That measure will take effect in the summer if it withstands a likely court challenge.
"I celebrate the vote in the Maryland Senate passing the Marriage Equality bill, and applaud Gov. Martin O'Malley, who will sign it," said the Rev. Michael Schuenemeyer, UCC executive for health and wholeness advocacy.
"Now it is up to the fair-minded citizens of Maryland to uphold equality and fairness," added Schuenemeyer. "It can be done, and I know that many of our UCC churches and members will be working hard to make civil marriage available to everyone."
State elections officials say they are already getting calls seeking information on how to overturn the Senate's vote. Even the bill's staunchest supporters expect its opponents to easily gather the 55,736 signatures required to put the question on the Nov. 6 ballot.
To qualify for the ballot, opponents will need to gather one-third of the required signatures — 18,579 — by May 31 and the remainder by June 30.
Six states and the District of Columbia already issue same-sex marriage licenses ––Connecticut, Iowa, Massachusetts, New Hampshire, New York and Vermont. Five states –– Delaware, Hawaii, Illinois, New Jersey and Rhode Island –– allow civil unions that provide rights similar to marriage.
New Jersey lawmakers approved same-sex marriage this month, but Gov. Chris Christie vetoed the legislation. He has said voters should decide the issue in a statewide referendum.
Voters in Minnesota and North Carolina, meanwhile, will consider proposals in November to ban gay marriage in those states. New Hampshire lawmakers also may consider a repeal of its same-sex marriage law, according to the National Organization for Marriage, which opposes same-sex marriage.
Lawsuits seeking to expand civil unions or turn back laws banning same-sex marriages are working through the courts in at least 12 states, including Hawaii, Minnesota and California, the organization said.
The recent flurry of activity is a stark change from two decades ago, when the issue of same-sex marriage first gained national attention. A decade ago, no states allowed such unions.
In 1996, when Congress defined marriage solely as a union between a man and a woman, 68 percent of Americans opposed same-sex marriage, with 27 percent in favor, according to polling by Gallup. By May 2011, the lines had crossed, with 53 percent of Americans in favor and 45 percent opposed, the pollster said.
"We have strong feelings on each side of the issue, but most people have other important things on the top of their minds," said Carrie Evans, executive director of Equality Maryland and a leading advocate of the legislation.
With a string of recent advances in other states, Evans thinks voters are becoming comfortable with the concept of marriage equality.
"People are really starting to understand that this is happening in the world and the sky isn't falling," she said.