The Justice Department on Monday will instruct all of its employees across the country, for the first time, to give lawful same-sex marriages sweeping equal protection under the law in every program it administers, from courthouse proceedings to prison visits to the compensation of surviving spouses of public safety officers.

In a new policy memo, the department will spell out the rights of same-sex couples, including the right to decline to give testimony that might incriminate their spouses, even if their marriages are not recognized in the state where the couple lives.

Under the Justice Department policy, federal inmates in same-sex marriages will also be entitled to the same rights and privileges as inmates in heterosexual marriages, including visitation by a spouse, escorted trips to attend a spouse’s funeral, correspondence with a spouse, and compassionate release or reduction in sentence based on the incapacitation of an inmate’s spouse.

In addition, an inmate in a same-sex marriage can be furloughed to be present during a crisis involving a spouse. In bankruptcy cases, same-sex married couples will be eligible to file for bankruptcy jointly. Domestic support obligations will include debts, such as alimony, owed to a former same-sex spouse. Certain debts to same-sex spouses or former spouses should be excepted from discharge.

“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,” Attorney General Eric H. Holder Jr. said in a speech Saturday night at the Human Rights Campaign’s Greater New York Gala at the Waldorf Astoria in New York, where he announced the new policy.

“This landmark announcement will change the lives of countless committed gay and lesbian couples for the better,” Human Rights Campaign President Chad Griffin said in a statement. “While the immediate effect of these policy decisions is that all married gay couples will be treated equally under the law, the long-term effects are more profound. Today, our nation moves closer toward its ideals of equality and fairness for all.”

The Justice Department’s new policy comes three years after it said it would not defend cases in court involving the Defense of Marriage Act anymore. Last year, the Supreme Court ruled that a key part of DOMA was unconstitutional.

The ruling “marked a major victory for the cause of equal protection under U.S. law, and a significant step forward for committed and loving couples throughout the country,” Holder said Tuesday in Sweden during an address to the Swedish parliament.

In January, Holder intervened in the legal battle over same-sex marriage in Utah and announced that the more than 1,300 same-sex marriages that took place there in December and January are considered legal under federal law, even though a step by the Supreme Court cast doubt on the marriages and state officials would not recognize those unions.

On Saturday, the National Organization for Marriage released a statement decrying the policy move.

“This is just the latest in a series of moves by the Obama administration, and in particular the Department of Justice, to undermine the authority and sovereignty of the states to make their own determinations regulating the institution of marriage,” Brian Brown, the group’s president, said in the statement. “The American public needs to realize how egregious and how dangerous these usurpations are and how far-reaching the implications can be. The changes being proposed here . . . serve as a potent reminder of why it is simply a lie to say that redefining marriage doesn’t affect everyone in society.”

The Justice Department has already approved policy changes by other federal agencies to extend federal benefits to same-sex married couples.

Last summer, the Office of Personnel Management announced that federal employees in same-sex marriages could apply for health, dental, life, long-term care and retirement benefits. The Department of Health and Human Services said that legally married same-sex seniors on Medicare would be eligible for equal benefits and joint placement in nursing homes.

The Social Security Administration will pay death benefits to survivors of a same-sex marriage. The Department of Homeland Security will treat same-sex spouses equally for the purposes of obtaining a green card if the spouse is a foreign national. And the IRS has begun treating same-sex marriages equally for tax-filing purposes.

“We are, right now, in the middle of marking a number of 50-year anniversaries of key milestones in the civil rights movement,” Holder said Saturday night. “And yet, as all-

important as the fight against racial discrimination was then, and remains today, know this: My commitment to confronting discrimination based on sexual orientation or gender identity runs just as deep.”

Holder made a similar statement in favor of expanding LGBT rights in Sweden on Tuesday.

The new policy will have “important, real-world implications for same-sex married couples that interact with the criminal justice system,” Holder said.

The Justice Department will also recognize same-sex couples in a number of key benefits programs it administers, such as the Radiation Exposure Compensation Program, the September 11th Victim Compensation Fund and the Public Safety Officers’ Benefits Program, which provides death benefits and educational benefits to surviving spouses of public safety officers.

“This program is one way that we, as a country, stand by the families of those who put themselves in harm’s way to keep our communities safe, and we must never do that selectively,” Holder said. “When any law enforcement officer falls in the line of duty or is gravely injured, the federal government should stand by that hero’s spouse — no matter whether that spouse is straight or gay.”