People for the American Way:

“It’s high time this attorney general resigned. Alberto Gonzales was the 'Enabler General' for the imperial Bush presidency. He undermined the Constitution, made a mockery of the rule of law, and turned the Justice Department into an arm of the Bush Administration’s political operation.

Update: ACLU weighs in.

“Alberto Gonzales will follow Mitchell Palmer as one of the worst attorneys general in U.S. history,” said Anthony D. Romero, ACLU Executive Director. “But Gonzales’ resignation doesn’t put an end to the widespread abuse of executive powers. The White House may claim that Gonzales’ resignation restores the rule of law, but if anything, his departure highlights the need for increased scrutiny and accountability.”

....This man, who swore to uphold the Constitution, instead flouted it, and consistently put partisan political considerations over the rule of law,” said Caroline Fredrickson, Director of the ACLU Washington Legislative Office. “He twisted our Constitution and created a legal framework that paved the way for tremendous and growing abuses of power by the executive branch. He spied on Americans, attempted to justify torture, and worked to strip away our most sacred rights and freedoms – all to further the president’s political agenda. Congress must not accept Gonzales as the administration’s latest sacrificial lamb. Congress must conduct more oversight and restore our Constitution, our world status and American values.”