WASHINGTON – Attorney General Alberto Gonzales’ resignation Monday after months of draining controversy drew expressions of relief from Republicans and a vow from Democrats to pursue their investigation into fired federal prosecutors.

President Bush, Gonzales’ most dogged defender, told reporters he had accepted the resignation reluctantly. “His good name was dragged through the mud for political reasons,” Bush said.

The president named Paul Clement, the solicitor general, as a temporary replacement. With less than 18 months remaining in office, there was no indication when Bush would name a successor – or how quickly or easily the Senate might confirm one.

Apart from the president, there were few Republican expressions of regret following the departure of the nation’s first Hispanic attorney general, a man once hailed as the embodiment of the American Dream.

“Our country needs a credible, effective attorney general who can work with Congress on critical issues,” said Sen. John Sununu of New Hampshire, who last March was the first GOP lawmaker to call on Gonzales to step down. “Alberto Gonzales’ resignation will finally allow a new attorney general to take on this task.”

Sen. Chuck Grassley, R-Iowa, added, “Even after all the scrutiny, it doesn’t appear that Attorney General Gonzales committed any crimes, but he did make management missteps and didn’t handle the spotlight well when they were exposed.”

Democrats were less charitable.

Under Gonzales and Bush, “the Department of Justice suffered a severe crisis of leadership that allowed our justice system to be corrupted by political influence,” said Sen. Patrick Leahy, D-Vt., who has presided over the investigation into the firings of eight prosecutors whom Democrats say were axed for political reasons.

Majority Leader Harry Reid, D-Nev., said the investigation would not end with Gonzales’ leaving.

“Congress must get to the bottom of this mess and follow the facts where they lead, into the White House,” said the Nevada Democrat.

Gonzales also has struggled in recent months to explain his involvement in a 2004 meeting at the hospital bedside of then-Attorney General John Ashcroft, who had refused to certify the legality of Bush’s no-warrant wiretapping program. Ashcroft was in intensive care at the time.

More broadly, the attorney general’s personal credibility has been a casualty of the multiple controversies. So much so that Sen. Arlen Specter, senior GOP member of the Judiciary Committee, told him at a hearing on the prosecutors that his testimony was “significantly if not totally at variance with the facts.”

The speculation about a successor began immediately, and included Homeland Security Secretary Michael Chertoff; Asa Hutchison, former head of the Drug Enforcement Administration; former soliticor general Ted Olson; and Larry Thompson, who was the second-ranking official at the Justice Department in Bush’s first term.