For months, the Democratic-controlled Congress and the Bush administration have been locked in a potentially historic battle over whether top White House aides will ever testify about the controversial firings of federal prosecutors in late 2006.

But now these two branches of government may have hit a roadblock on their way to a constitutional confrontation.

A federal judge on June 23 appeared very reluctant to rule on the administration's broad claim of executive privilege in the case. Historically, the judiciary has been hesitant to meddle in this area unless the stakes are clear and high.

"Whether I rule for the executive branch or I rule for the legislative branch, I'm going to disrupt the balance [of powers], said US District Judge John Bates.

For Bush officials this attitude may be a bit of good news. It means a new president will likely be in office before the dispute is resolved – and the next administration, or the next Congress, may decide to just drop the whole thing.

Judge Bates "might just let the clock run out on this," says Carl Tobias, a law professor at the University of Richmond in Virginia.

At issue in a three-hour hearing in a federal courtroom on June 23 was a demand from the House Judiciary Committee for documents and testimony from the president's chief of staff, Joshua Bolten, and former counsel, Harriet Miers, about the US attorney dismissals.

Panel members say they need that information to help determine whether the Bush White House improperly politicized some of the nation's top federal prosecutor jobs.

The Bush administration argues that Mr. Bolten and Ms. Miers are immune from such requests due to executive privilege – the legal doctrine stating that discussions between a president and his advisers can be kept secret.

Congessional-White House disputes over executive privilege are fairly common, but most are settled short of a lawsuit, say analysts. Courts don't like to handle them, and for the disputants they take too much time, money, and attention away from other business.

They are generally settled in the political arena, with either Congress or the White House backing down. Or Congress can use other methods of trying to enforce compliance, including employing its power of the purse to withhold funds requested by the administration.

Judge leery of White House claims

At times in the June 23 hearing, Bates seemed skeptical of the administration's claims. In the case, the Justice Department is holding that senior presidential advisers under all circumstances are immune from congressional subpoenas.

But the judge also appeared to side with the argument that Congress perhaps had issued its subpoenas too quickly. Lawmakers could have refused to confirm further judicial nominees, he said, and waited to see if such pressure produced the desired testimony before rushing to the courthouse.

Bates even mentioned that the House could hold Miers and Bolten in contempt, and order their arrest and detention in the Capitol.

In response, House counsel Irvin B. Nathan said he doubted that arresting a member of the administration would bring a tidy end to such a dispute, and filing a lawsuit was a better way to proceed.

The administration's claims of executive privilege in this case are exceptionally broad, notes Professor Tobias. The White House is essentially arguing that all conversations of all senior officials – even those that don't involve the president – are exempt from court-ordered disclosure.

"Congress probably has the better of the argument here," says Tobias.

But even if the White House is asking for too much, Congress is asking for quite a bit in terms of disclosure as well, he adds.

The Bush administration may resent what it feels is a fishing expedition, and Bates – a Bush nominee – might agree.

"This is really a very difficult case," says Tobias.

But it may not be the last such case of the Bush administration. On June 20, the president asserted executive privilege in withholding from the House Oversight and Government Reform Committee documents related to the decision of the Environmental Protection Agency to weaken decisions on the control of smog and greenhouse gases.

Claims of interference with EPA

The chairman of the House Oversight panel, Rep. Henry Waxman (D) of California contends that the White House intervened with the EPA to produce more industry-friendly smog standards, and to deny California and a dozen other states permission to control greenhouse gases on their own.

The administration has already produced thousands of pages of papers dealing with these decisions, but panel investigators claim some important documents are still being held back.

"I have a clear sense that their assertion of this privilege is self-serving and not based on the appropriate law and rules," said Representative Waxman on June 20.

•Material from the Associated Press was used in this report.