WASHINGTON, Nov. 20  Who says the Senate cannot act quickly? It conducted a full day’s business in less than 30 seconds on Tuesday.

Of course, there was no real business to conduct. But fearing that President Bush would again use a Congressional recess to install disputed executive branch appointees without Senate confirmation, Democrats convened the Senate for the first of four microsessions to be held during the holiday break, precisely to thwart such an end run.

“I am glad to see the leadership stepped up here,” said Jim Webb, the junior senator from Virginia, called upon by the majority to open the Senate with a skeleton staff for the express purpose of immediately closing it down.

Senator Harry Reid of Nevada, the majority leader, chose to schedule the so-called pro forma sessions because Mr. Bush took advantage of past recesses to install nominees including John R. Bolton, as ambassador to the United Nations, and, most recently, Sam Fox, a donor to Swift Boat Veterans for Truth, as ambassador to Belgium. This time, Democrats were particularly suspicious of plans to appoint as surgeon general a nominee they oppose.