President Obama's decision to stop defending the Defense of Marriage Act in federal court has sparked a flurry of debate over whether the move signals a dangerous power grab by the executive branch.
"The president is replacing the rule of law with the rule of Obama," said former House Speaker Newt Gingrich. "The president swore an oath on the Bible to ensure that the laws be faithfully executed, not to decide which laws are and which are not constitutional."
House Judiciary Committee Chairman Rep. Lamar Smith called it the "politicization of the Justice Department -- when the personal views of the president override the government's duty to defend the law of the land."
In a letter to members of Congress Wednesday, Attorney General Eric Holder explained that Obama determined that DOMA, which defines marriage for federal purposes as only between one man and one woman, "violates the equal protection component of the Fifth Amendment" and therefore is not obligated to defend it.
Legal experts say the decision not to defend a federal law, while rare and controversial, is not unprecedented.
Most recently, in 1996, President Clinton warned he would not defend a law requiring the military to discharge H.I.V.-positive service members because he found it unconstitutional. Other cases have involved laws imposing sex discrimination or unfairly targeting specific individuals.
But some have warned that unlike previous cases, in which the unconstitutionality of the law seemed reasonably apparent, the questions surrounding DOMA are not supported by a legal consensus or judicial precedent.
"This theory is not compelled by case law. Rather, it's a possible result, one that is popular in some circles and not in others but that courts have not weighed in on much yet," wrote George Washington University law professor Orin Kerr in a blog post.
"The Obama administration has moved the goalposts of the usual role of the Executive Branch in defending statutes," he wrote.
Kerr says the president's action could undermine the role of the impartial court system if the Justice Department can conduct its own constitutional reviews of challenged laws, and then exercise discretion in whether to defend them.
The executive branch's "duty to defend" a law, even if the administration finds it politically unpopular, has been tradition for decades.
If Obama can choose not to defend DOMA on constitutional grounds, some critics say, a future Republican president may be able to do the same to Democrats' controversial health care reform law.
DOMA Still in Effect
Supporters of Obama's decision to drop a legal defense of DOMA note, however, that several lower courts have found the law unconstitutional.
Moreover, administration officials say, deciding not to defend DOMA in court does not mean the law is overturned.
"DOMA will continue to remain in effect unless Congress repeals it or there is a final judicial finding that strikes it down," Holder said Wednesday, "and the president has informed me that the Executive Branch will continue to enforce the law."
Enforcement of the law means the federal government will continue to deny recognition to same-sex couples for a litany of federal benefits afforded to their married heterosexual counterparts.
Legal defenders of the administration's decision also point out that outside groups are able to step in for government lawyers and mount a defense of DOMA in court if they so choose.
"Informing the courts of the administration's view that a law is unconstitutional, while facilitating the participation of amicus who will argue in defense of the law, is respectful of the role of the other branches, both Congress and the judiciary," said law professor and former Clinton administration Solicitor General Walter Dellinger.
Brian Brown, president of the National Organization for Marriage, said he believes Republican lawmakers are preparing to intervene.
"We've been in a lot of discussions with leadership with members of Congress and look, they're looking at the case, they're making decisions as we speak. And I expect them to step in and defend the law," he said on ABC News' "Top Line."
Regardless of who stands in to legally defend DOMA, legal experts point out, a federal court -- likely the Supreme Court -- will ultimately decide whether DOMA is constitutional.