Senator Harry Reid of Nevada, the Democratic leader, characterized Mr. Bush's move as "the latest abuse of power by the Bush White House," while another Democrat, Senator Frank Lautenberg of New Jersey, said in a statement that "even while the president preaches democracy around the world, he bends the rules and circumvents the will of Congress" at home.

Democrats were also angry about the refusal of the White House to turn over documents related to Mr. Bolton's service at the State Department as well as his caustic comments about the United Nations. In the 1990's, Mr. Bolton said that several floors of the United Nations headquarters could be lopped off without being missed.

In his remarks, Mr. Bush blamed the hold-up on "partisan delaying tactics by a handful of senators," but Democrats countered that the handful numbered at least 42, including one Republican. "And it was growing," said Senator Christopher J. Dodd, Democrat of Connecticut, who led the Senate opposition to Mr. Bolton. "It may have been more people if we had ever gotten a vote."

Senator George V. Voinovich, the Ohio Republican whose opposition to Mr. Bolton was the catalyst for the Senate's refusal to confirm him, told reporters that he intended to send Mr. Bolton a copy of a Christian book that has served him well since his days as mayor of Cleveland in the 1980's: "The Heart and Soul of Effective Management" by James F. Hind.

"It's basically a Christian approach to managing and motivating people," Mr. Voinovich said, "that I thought he might read and perhaps ponder and take into consideration in terms of how he treats people up at the United Nations."

Still, Democratic aides on Capitol Hill acknowledged that there was little their party could do beyond criticizing Mr. Bolton's appointment, which senators did in statements of outrage that were sent via e-mail to reporters even as Mr. Bush was still speaking in the Roosevelt Room. By 10:04 a.m., three minutes after Mr. Bush began his remarks, Senator Edward M. Kennedy had sent out a statement that called the recess appointment "a devious maneuver" that "further darkens the cloud over Mr. Bolton's credibility at the U.N."

Mr. Bolton's appointment came as Democrats on Capitol Hill were in a new fight with the White House over the records of Mr. Bush's Supreme Court nominee, Judge John G. Roberts, when he worked in the office of the solicitor general. But Democrats, wary that their anger over Mr. Bolton might be seen as retaliation against Judge Roberts, said that the two nominations were distinct and that they did not expect Mr. Bolton's troubles with the Senate to affect Judge Roberts' confirmation hearings in September.