(CNN) -- In a major milestone for gay rights, the United States government plans to expand recognition of same-sex marriages in federal legal matters, including bankruptcies, prison visits and survivor benefits.
Attorney General Eric Holder said the Justice Department will issue a memo Monday that recognizes same-sex marriages "to the greatest extent possible under the law."
The federal expansion will include 34 states where same-sex marriage isn't legal, but the new federal benefits being extended to those states will apply only where the U.S. government has jurisdiction, Holder said.
For example, a same-sex couple legally married in Massachusetts can now have their federal bankruptcy proceeding recognized in Alabama, even though it doesn't allow same-sex marriages. In the past, the U.S. government could challenge the couple's joint bankruptcy because Alabama doesn't recognize same-sex marriage.
Holder's announcement was revealed in an advance copy of a Saturday night speech at the Human Rights Campaign's gala in New York City. At its blog, the advocacy group cheered what it called a "landmark announcement" that it "will change the lives of countless committed gay and lesbian couples for the better."
But Brian Brown, president of the National Organization for Marriage, criticized what he called the latest move by President Barack Obama's administration "to undermine the authority and sovereignty of the states to make their own determinations regulating the institution of marriage."
"The American public needs to realize how egregious and how dangerous these usurpations are and how far-reaching the implications can be," Brown said in a statement. "The changes being proposed here to a process as universally relevant as the criminal justice system serve as a potent reminder of why it is simply a lie to say that redefining marriage doesn't affect everyone in society."
The move affects how millions of Americans interact with their federal government, including bankruptcy cases, prison visitation rights, survivor benefits for police officers and firefighters killed on the job, and the legal right to refuse to testify to incriminate a spouse.
Holder compared his work for the gay rights cause to the 1960s civil rights struggle and then- Attorney General Robert F. Kennedy's support for equality.
"This means that, in every courthouse, in every proceeding, and in every place where a member of the Department of Justice stands on behalf of the United States -- they will strive to ensure that same-sex marriages receive the same privileges, protections and rights as opposite-sex marriages under federal law," Holder said of his initiative.
Under the new policy, the Justice Department will recognize that same-sex spouses of individuals involved in civil and criminal cases should have the same legal rights as all other married couples -- including the right to decline to give testimony that might incriminate their spouses.
Also, the government won't contest same-sex married couples their rights in states where previously prosecutors could argue that the marriage is not recognized in the state where the couple lives, Holder said.
Couples in same-sex marriages will be allowed to file for bankruptcy as a couple. This ensures alimony and domestic support debts aren't discharged in bankruptcy cases. Federal inmates with same-sex spouses will now have full visitation, compassionate release and other benefits.
The Justice Department's policy change will extend benefits to same-sex couples who benefit from federal programs such as the Sept. 11 Victim Compensation Fund, Radiation Exposure Compensation program and to the families of police officers and firefighters who receive benefits from the Public Safety Officers' Benefits Program.
"Just like during the civil rights movement of the 1960s, the stakes involved in this generation's struggle for LGBT equality could not be higher," Holder said. "As attorney general, I will not let this Department be simply a bystander during this important moment in history."