Maryland Attorney General Douglas Gansler issued a long-awaited opinion Wednesday saying same-sex marriages performed in other states or countries most likely would have full legal standing in the state.

But in his 53-page legal opinion, Gansler said the Maryland Court of Appeals would have the final say in the matter should opponents of same-sex marriage choose to contest the legal standing of married same-sex couples living in or visiting the state.

Gansler’s opinion comes one week before a law allowing same-sex marriages to be performed in D.C. is expected to take effect March 3. Same-sex couples in Maryland have said they would likely make wedding plans in the District in response to a favorable opinion from Gansler.

The attorney general’s opinion comes nine months after state Sen. Richard Madaleno (D-Montgomery County), who is gay, asked Gansler to issue an official opinion on the question of whether the state could legally recognize same-sex marriages from other jurisdictions.

“You have asked whether those marriages may be recognized under state law,” Gansler said in his opinion, which is addressed to Madaleno. “The answer to that question is clearly ‘yes.’”

Madaleno could not immediately be reached for comment, but he told the Washington Post in a brief interview that changes in state policy could now result from a court ruling, legislation or administrative action, though none of those is imminent.

Gansler says in the opinion that while he believes the legal concept of state “public policy” favors recognition of out-of-state gay marriages, others might raise legal grounds to contest that view.

In particular, he points to the 2007 ruling by the Maryland Court of Appeals upholding the state’s marriage law banning same-sex marriages from being performed in the state. In that 4-3 ruling denounced by LGBT activists, the court ruled that restricting marriage to a man and a woman doesn’t discriminate against same-sex couples or deny them rights under the state constitution. The court held that the ban on same-sex marriage instead promotes the state’s “interest” in traditional heterosexual marriage as a means of fostering procreation and protecting children.

But Gansler says in his opinion that the appeals court decision should not be a key factor in determining whether Maryland could recognize same-sex marriages from other jurisdictions.

“The Court of Appeals would start from the general principle that a marriage that is valid in the place of celebration remains valid in Maryland,” he said in his opinion. “There are exceptions to that rule if the particular marriage is contrary to a strong state public policy. A statute that limits marriage in Maryland to opposite-sex couples could be said to embody a policy against same-sex marriage.”

However, Gansler noted that the Court of Appeals has not prevented the state from recognizing various types of marriages performed in other states that are not allowed to be performed in Maryland under the state’s marriage law. Among them are common law marriages, which are recognized in many other states. The Court of Appeals also upheld a Rhode Island marriage between an uncle and a niece, even though the Maryland marriage law prohibits such a marriage, Gansler says in his opinion.

“While the matter is not free from all doubt, in our view, the court is likely to respect the law of other states and recognize a same-sex marriage contracted validly in another jurisdiction,” he says. “In light of Maryland’s developing public policy concerning intimate same-sex relationships, the court would not readily invoke the public policy exception to the usual rule of recognition.”

In response to a second question raised by Madaleno, Gansler says in his opinion that Maryland Gov. Martin O’Malley does not have authority to issue an executive order recognizing same-sex marriages from other jurisdictions.

In his May 19, 2009, letter to Gansler requesting the same-sex marriage recognition opinion, Madaleno pointed out that New York Gov. David Paterson issued such an order, clearing the way for New York to recognize out-of-state same-sex marriages, even though the legislature had not approved a same-sex marriage bill.

“An executive order of the governor must be consistent with existing Maryland law, as enacted by the General Assembly and construed by the courts,” Gansler says.

LGBT rights groups hailed Gansler’s opinion as an important breakthrough for the marriage equality movement.

“Today is a day to celebrate,” said Morgan Meneses-Sheets, executive director of Equality Maryland, a state LGBT advocacy group.

“Equality Maryland applauds a favorable opinion released by the Office of Attorney General Doug Gansler that states that the marriages of same-gender couples legalized in other jurisdictions have standing to be honored here at home.”

But Rick Bowers, director of Christian Impact Alliance, a Maryland group opposed to same-sex marriage, said Gansler acted without legal authority to issue such a ruling.

“The governing body over a decision like this should be the General Assembly or the people of the state of Maryland through a vote by referendum,” Bowers said.

Gay rights groups, however, disputed Bowers assessment, saying Gansler has authority to issue such an opinion.

Lambda Legal, a national LGBT group, praised Gansler’s opinion for “saying that recognition of out-of-state marriages of same-sex couples is consistent with Maryland law.”

Susan Sommer, director of the group’s Constitutional Litigation program, said the Gansler opinion “should bring some peace of mind to married same-sex couples and their families in Maryland as this state aligns itself with New York, making clear that there is no gay exception to long-standing marriage recognition law.”

Evan Wolfson, executive director of the national same-sex marriage advocacy group Freedom to Marry, said he was confident that the Maryland Court of Appeals would uphold Gansler’s assessment that valid same-sex marriages from other jurisdictions have full legal standing in Maryland.

“Maryland’s typical practice, like all states historically, is to honor marriages rather than destabilize them,” Wolfson said. “The Maryland Attorney General is concluding, looking at Maryland law, that there is no reason for a gay exception to that tradition and common sense practice.”

While praising Gansler’s opinion as an important development for same-sex marriage equality, some LGBT organizations said it focuses attention on the need for all states to adopt same-sex marriage laws.

“Today’s opinion by the Maryland Attorney General only continues to further highlight the burdensome patchwork of unequal laws same-sex couples face across the country,” said Joe Solmonese, president of the Human Rights Campaign. “With every step that is taken in the progress toward full equality, it becomes more and more obvious that separate is not equal and marriage by any other name is not marriage.”

The action by Gansler on Wednesday also comes less than a month after the Maryland House Judiciary Committee voted 12-8 to defeat a bill that would have banned same-sex marriage in the state. The measure was introduced by Del. Emmett Burns (D-Baltimore County), who said he anticipated Gansler’s opinion would back same-sex marriage recognition.

Maryland Del. Don Dwyer (R-Anne Arundel County), meanwhile, is “definitely” moving ahead with plans to file impeachment papers against Gansler for his same-sex marriage recognition opinion, according to spokesperson Louisa Baucom.

“His position about the opinion is that Attorney General Gansler had no right to issue the opinion, regardless of what the opinion is — that his constitutional limitations prohibit that,” Baucom said.

“He will be drawing up letters of impeachment against Attorney General Gansler,” she said, adding that the charges would be based on “violation of his oath of office.”