WASHINGTON -- Stating that he has broad discretion to hire and fire federal prosecutors as he sees fit, President George W. Bush stood by embattled Attorney General Alberto Gonzales on Tuesday, insisting that the Justice Department did nothing wrong when it fired eight federal prosecutors earlier this year.

Bush also said he will fight the Congress if it chooses to issue subpoenas to force political aide Karl Rove and other White House officials to testify about the firings.

"We will not go along with a partisan fishing expedition aimed at honorable public servants," Bush said from the White House. "I proposed a reasonable way to avoid an impasse."

"There's no indication ... that anybody did anything improper," he said.

Democrats' response to Bush's offer was swift and firm. "Testimony should be on the record and under oath. That's the formula for true accountability," said Patrick Leahy, chairman of the Senate Judiciary Committee.

Sen. Charles Schumer, D-N.Y., said he would also press for White House aides to testify under oath.

Meanwhile, the Senate voted overwhelmingly Tuesday to end the Bush administration's ability to unilaterally fill U.S. attorney vacancies as a backlash to Attorney General Alberto Gonzales' firing of the prosecutors.

The 94-2 vote would overturn a Justice Department-authored provision in the Patriot Act that had allowed the attorney general to appoint U.S. attorneys without Senate confirmation.

Democrats say the Bush administration used the law to benefit White House loyalists.

Under the bill, which has yet to be considered in the House, there would be a 120-day deadline for the administration to appoint interim prosecutors. If the interim appointment is not confirmed by the Senate in that time, a permanent replacement would be named by a federal district judge.

President George W. Bush called Gonzales earlier in the day to reaffirm his support for him.

The White House said Bush and Gonzales spoke for several minutes about the political uproar over the firings.

The White House is denying that it's looking for possible successors for Gonzales. A spokeswoman said, "Those rumors are untrue."

The Justice Department released about 3,000 new e-mails about the firings Monday night.

The new e-mails show that Justice Department officials wanted to quickly get the firings behind them after Republican losses in the midterm elections and sought a "green light" from the White House to go ahead with them.

Former White House counsel Harriet Miers wrote in one e-mail to Kyle Sampson, Gonazales' former chief of staff, that she wasn't sure if the firings would "require the boss's attention." That was an apparent reference to the president.

In Monday's press briefing, White House spokesman Tony Snow said that the president continued to have full confidence in Gonzales.

Tancredo Wants Gonzales To Resign Presidential hopeful Tom Tancredo has joined the growing chorus of lawmakers calling for U.S. Attorney General Alberto Gonzales to resign -- only not for the usual reason.

Unlike others criticizing Gonzales over the recent firing of eight U.S. attorneys, the Colorado Republican said the embattled attorney general should go because of "a series of leadership failures" -- chiefly his handling of illegal immigration prosecutions.

"Gonzales' legacy at the (Justice Department) has been one of misplaced priorities, political miscalculation, and a failure to enforce the laws which he has sworn to uphold," Tancredo said in a statement Tuesday. "I think that it is time for him to move on."

Tancredo said that he doesn't believe Gonzales' handling of the prosecutors' firings alone warrants his dismissal, but "his total mishandling of the affair is simply the latest in a series of leadership failures at the Justice Department."

Tancredo faulted several Justice Department decisions dealing with border crimes, including the prosecution of two border patrol agents for shooting a Mexican drug smuggler and trying to cover it up.

Fired Attorneys Rated

A Syracuse University study shows that Six of the eight U.S. attorneys fired by the Justice Department ranked in the top third among their peers for the number of prosecutions filed last year.

Five of the eight were among the government's top performers in winning convictions.

Four also rated high in pursuing drug cases.

Only one of the eight received a better-than-average ranking in prosecuting weapons cases.

The analysis undercuts Justice Department claims that the prosecutors were dismissed because of lackluster job performance.

Immigration cases -- a top Bush administration priority, especially in states along the porous Southwest border -- helped boost the total number of prosecutions for U.S. attorneys in Arizona, Nevada, New Mexico, San Diego, San Francisco and Seattle.