Today, the US Senate authorized subpoenas compelling Bush administration officials to give sworn testimony to Congress regarding the circumstances under which eight federal prosecutors were fired in December. However, there are no immediate plans to issue the subpoenas.

“We're authorizing that ability but we're not issuing them,” said Sen. Charles Schumer (D-N.Y.). “It'll only strengthen our hand in getting to the bottom of this.”

Congressional Republicans are also urging caution. “I counsel my colleagues, both Democrats and Republicans, to work hard to avoid an impasse. We don't need a constitutional confrontation,” said Sen. Arlen Specter of Pennsylvania, the panel’s ranking Republican.

President Bush will almost certainly invoke Executive Privilege if the subpoenas are served.

Thus, what began as a scandal over political interference in the federal administration of justice may soon approach a constitutional crisis, and the battle between Congress and the White House could well end up in the US Supreme Court.

President Bush has rejected outright the prospect of his aides testifying under oath in public, arguing that it would set a harmful precedent for the separation of powers and damage the institution of the presidency.

Instead, he offered to allow senior administration officials – including top Bush political advisor Karl Rove, former White House counsel Harriet Miers, and the embattled US Attorney General’s former chief of staff Kyle Sampson – to privately discuss the attorneys’ dismissals with Congress.

Mr Bush’s offer includes stringent conditions that there be no public testimony, no testimony under oath, no transcripts of discussions and no calling witnesses back to answer further questions.

These provisos have not gone over well with Congressional Democrats.

“Anyone who would take that deal isn’t playing with a full deck,” said Senate majority leader Harry Reid (D-Nev.), who added that it would be “outrageous” to allow Mr Rove to testify off the record. “Congress and the American people deserve a straight answer. If Karl Rove plans to tell the truth, he has nothing to fear from being under oath like any other witness.”

Rep. Bill Delahunt (D-Mass.) agreed, “To insist that these interviews be conducted privately, not under oath, and with no transcript, I would suggest borders on insulting this committee and this Congress.”

But Mr Bush defended the offer: “The proposal we put forward is a good one. There really is a way for people to get information. We’ll just find out what’s on their mind.”

US Attorney General Alberto Gonzales and other Department of Justice officials initially told Congress that the dismissals of eight federal prosecutors had been carried out due to their poor job performance. Officials have since backed down from that claim, after the prosecutors’ favorable performance evaluations came to light.

The White House has continually argued that federal attorneys can be fired for any reason since they are “political” appointees who “serve at the pleasure of the President.”

However, critics counter that this is not the case if there is criminal wrongdoing.  Senate Judiciary Committee Chairman Patrick Leahy (D-Vt.) said that if an attorney is fired “to stop an ongoing investigation, then you do get into the criminal area.”

One of the fired attorneys, Carol Lam of California, successfully prosecuted Republican congressman Randy “Duke” Cunningham, who is now serving eight years in federal prison for conspiracy to commit bribery, mail fraud, wire fraud and tax evasion. On the basis of evidence uncovered in that case, Ms Lam had decided to broaden her investigation. Department of Justice e-mails released last week include one authored by Mr Sampson which referred to “the real problem we have right now with Carol Lam that leads me to conclude that we should have someone ready to be nominated on 11/18, the day her 4-year term expires.” This has raised suspicions that the Bush administration wanted to stop an investigation that targeted Republicans.

Meanwhile, David Iglesias of New Mexico, another of the fired attorneys, recently told Fox News, “Performance has nothing to do with this. This is a political hit.” Mr Iglesias said he was fired after Senator Pete Domenici (R-N.M.) complained to Bush administration officials that he hadn’t prosecuted Democrats over alleged voter fraud, despite there being insufficient evidence. Mr Iglesias also told the New York Times, “I thought I was insulated from politics, but now I find out that main Justice was up to its eyeballs in partisan political maneuvering.”

Atlee W. Wampler III, chairman of a national organization of former US attorneys and a prosecutor who served in the Carter and Reagan administrations, said in the same NYT report, “People who understand the history and the mission of the United States attorney and Justice Department — they are uniformly appalled, horrified.” He added, “Any American should be disturbed.”

Mr Rove became a central figure in the unfolding scandal when it was revealed that one of the dismissed attorneys, Bud Cummins of Arkansas, had been immediately replaced with Mr Rove’s protégé, Tim Griffin. Another of Mr Sampson’s e-mails confirmed that “getting him [Griffin] appointed was important to Harriet, Karl, etc.” Yet Congress had initially been assured that there had been no White House involvement in the attorneys’ firings.   

“After two months of stonewalling, shifting stories and misleading testimony, it is clear that we are still not getting the truth about the decision to fire these prosecutors and its cover-up,” said Linda Sanchez, who chairs the House judiciary subcommittee on commercial and administrative law which approved the subpoenas on Wednesday. “There must be accountability.”