Experts Say Obama's Recess Appointments Could Signify End to a Senate Role WASHINGTON - To many Republicans and some constitutional scholars, President Obama's decision last week to ignore a sitting Senate and sidestep the confirmation process for several appointees risked nothing short of an end to the Senate's role of providing advice and consent on presidential appointments. Senate Republicans had been using procedural rules and filibusters to block or delay the confirmation of nearly 200 agency nominations, leaving vital positions vacant and neutralizing agencies they did not like. That compelled Mr. Obama to escalate matters further on Wednesday, making recess appointments even though the Senate was technically not in recess. Senator Harry Reid of Nevada, the majority leader, began using pro forma sessions, lasting just seconds, in late 2007 to keep the Senate nominally in session and prevent President George W. Bush from making recess appointments. Republicans have responded with stalling tactics that have left 74 nominees pending consideration on the Senate floor and an additional 107 bottled up in committees, many of them for economic posts or to run initiatives that Republicans fiercely oppose. On Wednesday, Mr. Obama went where Mr. Bush had declined to go. He invoked his constitutional right to recess appointments to install four nominees - the first director of the Consumer Financial Protection Bureau, Richard Cordray, and three members of the National Labor Relations Board - effectively calling the pro forma Senate session illegitimate. Republicans, lawyers and parliamentary experts say the move, if it survives potential legal challenges, could herald an end to the Senate's constitutionally guaranteed right to advice and consent. Eric Ueland, who was chief of staff to former Senator Bill Frist, said that using Mr. Obama's logic, presidents could make recess appointments when the Senate chamber closed for as little as a night or a weekend. "If his position is ever upheld, it gives any president of any party at any time the undiluted power of naming any person to any position in the federal government," Mr. Ueland said. The White House counsel, Kathryn Ruemmler, said that such assertions were "belied by the Constitution, precedent and history." "The Senate is functionally in recess," Ms. Ruemmler said. The Senate minority cannot by procedural trick and from an empty chamber prevent the president from performing his constitutional duties. The White House and Senate Democrats say the experiences of Mr. Obama's nominees had become intolerable. In the two years that Mr. Bush had to contend with a Democratic Senate, 740 of his 981 nominees for civilian positions were confirmed, a rate of 75 percent. During the 112th Congress, 285 of Mr. Obama's 503 civilian nominees have been confirmed, or 57 percent, according to Senate statistics. In all, 18 Obama nominees have withdrawn their names after their nominations languished for months. For example, Peter Diamond, a Nobel Prize winner in economics, could not get a vote to join the Federal Reserve Board, and Terry Garcia, a top official at the National Geographic Society, gave up on his nomination to be deputy commerce secretary. Another nominee, Caitlin J. Halligan, spent more than 280 days awaiting a vote on her confirmation to the U.S. Court of Appeals for the District of Columbia Circuit before it fell to a filibuster. People still awaiting Senate action include nominees to be under secretary of the Treasury for domestic finance, deputy commerce secretary, deputy secretary of housing and urban development, federal housing commissioner, head of the Corporation for National and Community Service and assistant attorney general for tax policy. Senate Republicans made clear that they would use the filibuster to prevent anyone from being confirmed to lead the Consumer Financial Protection Bureau unless the law that created it in 2010 was altered to dilute the director's power or increase Congressional control. "The Republicans" goal here is not simply to object to people who have views they think are out of the mainstream, but to shut down parts of the government they don't like," said Senator Charles E. Schumer, Democrat of New York. Republicans say the White House and Senate Democrats share the blame. Democratic committee leaders are responsible for the scores of nominees that have not gotten through their panels, said Don Stewart, a spokesman for the Republican leader, Senator Mitch McConnell of Kentucky. Mr. McConnell was prepared to clear a long list of presidential nominees before the holiday break if the president had offered his assurance that he would not ram through recess appointments, Mr. Stewart added. Mr. Obama did not. But David S. Addington, former chief of staff to Vice President Dick Cheney, said all of that was beside the point. The president, he said, violated constitutional law. A previous version of this article incorrectly named the appeals court that Caitlin J. Halligan has been nominated to.