It’s looking likely Washington, D.C., residents will have a chance to vote early next year on whether to amend the city charter by unlinking the local budget from the congressional appropriations process, but the city’s key congressional advocates worry the effort will only backfire.

On Wednesday — one day after the D.C. Council unanimously approved legislation to place the referendum on ballots during the next scheduled election — Rep. Darrell Issa, R-Calif., used his first public comments regarding the referendum to question whether it would pass legal muster.

“If D.C. residents are being asked to vote on a legal, constitutional question, it isn’t a fair question to place to the people,” he said. “They are saying they want it, but it’s a legal decision on whether or not they can have it without congressional action.”

Proponents of the referendum, including the D.C. Council’s general counsel and activist groups such as DC Vote, say they are within their legal rights: The Home Rule Act of 1973 says nothing to prohibit the city from amending its charter to let D.C. spend its money without congressional approval.

A charter amendment through referendum, supporters say, would be the only way to achieve budget autonomy without policy riders, such as restrictions on local abortion funding. Issa, the chairman of the Oversight and Government Reform Committee, which has jurisdiction over the city’s governance, has been working since last year on a budget autonomy bill in Congress.

Critics of the referendum say that only Congress has the authority to grant the District budget autonomy. For D.C. to give itself the power to spend its own money, they say, would be violating the Antideficiency Act, which forbids federal entities — such as the federal city of D.C. — from spending funds before they are appropriated, in this case by Congress.

Issa, who in the past has described his role as somewhat akin to being D.C.’s “governor,” agrees with this legal assessment.

“What we want to do is give the District of Columbia the ability to spend their own raised funds with the recognition that, just like a state, they can’t raise funds that haven’t been appropriated by the government,” Issa said. “Currently they don’t have that authority, and no referendum can create that.”

Also, Issa predicts that the referendum’s appearance on a special-election ballot this spring would impede his ability to continue advocating for budget autonomy in the 113th Congress.

“The wishes of the people of the District of Columbia will never alienate me,” said Issa of speculation he would perceive the referendum push as a slight to his advocacy. “It does undermine my ability to get for them what I believe they want  . . .  because if it goes to a court challenge, as I am relatively sure it would, then it ties my hand until that’s over with, and that makes no sense.”

More appropriate, Issa said, would be a nonbinding, or advisory, referendum that expresses the desire of D.C. residents for budget autonomy.

“It has been my proposal all along that nonbinding referendums, a statement of the people, a redress to their government, is positive,” he said, “as opposed to essentially a partial secession from the union by saying, ‘We believe we have this inalienable right’ even though nowhere in the [Constitution] does this exist.”

Issa’s concern that the referendum push will backfire is shared by Mayor Vincent Gray and D.C. Del. Eleanor Holmes Norton. Although the two Democrats have said they would ultimately vote for the referendum if and when it appears on the ballot — Gray has not signed the authorizing legislation yet — the two local leaders believe that their best bet is working with Issa and others.

“[Norton] continues to pursue a budget autonomy bill in Congress in order to preserve the bipartisan congressional support that has been building, and that may prove necessary, considering the many difficult issues raised by the referendum,” Norton’s spokesman said in October. Norton would not comment further for this story.

In a letter to Democratic D.C. Council Chairman Phil Mendelson that was made public on Tuesday, Gray said he also feared that the referendum could stall the momentum that’s been steadily building around the budget autonomy issue on Capitol Hill.

“It would be unfortunate and unwise to short-circuit efforts by Congresswoman Norton and those of the House and Senate leaders who continue pressing forward on this clean budget-autonomy provision,” Gray wrote.

On Thursday, DC Vote spokesman James Jones articulated what Mendelson and others have argued all along: that this is an integral part of a two-track strategy.

“We share Darrell Issa’s desire to have a clean bill,” Jones said, “but recent history would suggest it is going to be very difficult to get a clean bill, and the people of the District shouldn’t be asked to wait.”

An earlier version of this article incorrectly stated the day the D.C. Council approved legislation to place a budget autonomy charter referendum on ballots. It was approved Dec. 4.