Bush from making appointments without the approval of the Democratic majority.
With the bang of a gavel, Democratic Senator Jim Webb declared the first session open on Sunday morning before closing it seconds later, without any of his colleagues present in the hall.
The brief ceremony will be repeated every two to three days until January 18, when lawmakers resume their work after the Christmas and New Year's holidays.
The Democratic majority is staging the move to avoid any formal recess for Congress extending over several days.
A recess would allow Bush to appoint ambassadors, judges and other top posts without seeking a Senate confirmation for his nominations.
Bush has previously used his authority to avoid drawn-out political battles with Democratic foes over controversial nominations, including that of foreign policy hawk John Bolton who was named in 2005 as Washington's UN ambassador during a congressional recess.
Bolton stepped down last December, just before the Democrats assumed control of Congress.
The "recess appointments" can last up to