A gay couple married under state law cannot give a joint contribution to a federal candidate if they make it from an individual banking account, the Federal Election Commission voted unanimously Thursday.

United for Marriage volunteer Marcos Garcia holds flags as he protests against the Defense of Marriage Act (DOMA) in front of the U.S. Supreme Court in Washington, March 27, 2013. REUTERS/Jonathan Ernst

In a somewhat emotional session, FEC commissioners lamented the fact they had no choice but to deny gay couples the same rights as straight ones, given the Defense of Marriage Act's legal requirements. Dan Winslow, a Republican candidate in next week's primary for the open Massachusetts Senate seat, had requested the advisory opinion.

"Mr. Engle, sometimes the law's an ass," declared FEC chair Ellen L. Weintraub, referring to the line from Charles Dickens' "Oliver Twist" in addressing Winslow's attorney Craig Engle.

Winslow donor Gerard R. Gershonowitz had sent a check from his personal account and asked for it to be attributed equally to him and Howard P. Johnson, the man to whom he is married under Massachusetts law.

Straight couples can make such a request under a provision in federal law, but the commission ruled in a 5-0 vote that they had no choice to reject it in this case.

"The Defense of Marriage Act is remarkably clear," said Donald F. McGahn II, the commission's vice chair. "We just can't disregard DOMA, regardless of what we think of it."

McGahn even pressed Engle to see if there was another conclusion the commission could have reached. "Do we have any other option here?" he asked.

Rather than specify what else the FEC could have done, Engle suggested he would raise the question again once the Supreme Court rules this year on whether the Defense of Marriage Act is constitutional.

"What I would say is we understand the answer," he said. "There is another answer that's possible, perhaps not at the moment, but that might be equally likely."

Couples can, regardless of their sexual orientation, make joint contributions to a federal candidate if they draw on a joint account.

But Engle said this option did not make up for the fact that gay couples had unequal status. "When Mr. and Mrs. Jones are treated one way and Mr. and Mr. Jones cannot because of how they hold their money, then there's confusion."

A few minutes later, commissioner Steven T. Walther observed that the current law has "pretty much tied our hands, but come on back."

"Count on it," Engle replied.

After the vote, Winslow issued a statement vowing to press the point once the Supreme Court rules on the gay marriage law.

"It's sad that in the 21st century the federal government is still denying certain people their First Amendment rights as guaranteed under the US Constitution," Winslow said. "However, I am encouraged by the FEC's advice that I return to them as soon as DOMA is overturned and they will happily reverse their decision.  I strongly believe DOMA will be overturned by the Supreme Court and I look forward to taking the FEC up on its offer as soon as that happens."