Holder's action will enable the government to extend eligibility for federal benefits to the couples. That means that same-sex couples who were married in Michigan can file federal taxes jointly, get Social Security benefits for spouses and request legal immigration status for partners, among other benefits.
The attorney general said the families should not be asked to endure uncertainty regarding their benefits while courts decide the issue of same-sex marriage in Michigan.
Holder did the same thing in Utah, where more than 1,000 same-sex couples got married, before the Supreme Court put those unions on hold in January after a federal judge overturned the conservative state's same-sex marriage ban in December.
Holder's decision came two days after Michigan Gov. Rick Snyder called the marriages performed last weekend legal but said Michigan won't recognize them.
U.S. District Judge Bernard Friedman struck down the gay marriage ban the day before.
Four counties took the extraordinary step of granting licenses on the Saturday before the 6th U.S. Circuit Court of Appeals ordered a temporary halt. The stay was extended indefinitely on Tuesday.
Snyder, who is a Republican, acknowledged that same-sex couples "had a legal marriage." But because of the court's stay, he added, the gay marriage ban has been restored. The governor's move closed the door, at least for now, to certain state benefits reserved solely for married couples. The American Civil Liberties Union has said more than 1,000 Michigan laws are tied to marriage.
Seventeen states and Washington, D.C., issue licenses for same-sex marriages. Since December, bans on gay marriage also have been overturned by courts in Texas, Oklahoma, Kentucky and Virginia, but appeals have put those cases on hold.
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