Washington (CNN) -- It's known as the "greatest deliberative body in the world," and with health care reform on the docket, the Senate's debate on the contentious bill could last through Congress' Christmas recess.
The goal, President Obama recently said, is for the Senate to pass legislation by Christmas -- though opposition from Republicans could derail the hope.
While the House has wrapped up much of its business for the year and has already passed its form of the reform bill, senators have been working around the clock and on weekends.
With the push to get a reform bill passed, Senate Majority Leader Harry Reid, who controls the legislative body's calendar, could keep the Senate in session into at least part of the break, which is set when the Senate is done with its business.
One senator has already prepared for the possibility.
Sen. Patrick Leahy, D-Vermont, said last week that he canceled plans with family in Vermont -- and even decided to ship a Christmas tree to Washington -- out of fears that there would be deliberations over the holiday break.
"My wife and I have canceled our plans to be in Vermont for Christmas, and I have to tell you that hurts," he told The New York Times. "We just called the people that we get our Christmas trees from every year and told them to ship it down here."
Senate Historian Don Ritchie said it's not unusual for the Senate to work until Christmas Day.
"In recent years, they've stayed until the 23rd, but it's quite possible they could work right through to the day before Christmas and come back the next week," he said.
According to Ritchie, who cited the Congressional Record, the House and Senate were in session during the holiday recess in the following sessions:
• 96th, because of a government shutdown (1979-1981)
• 91st, during the Vietnam War (1969-1971)
• 88th, after President John F. Kennedy's assassination (1963-1965)
• 81st, because of the Korean War (1949-1951)
• 77th and 76th, because of World War II (1939-1943)
As the health care battle continues, "It is quite possible" that senators could work during this recess, Ritchie said. He added that while it's "fairly uncommon," it's not unprecedented.
But the Senate didn't always have a holiday recess.
"In the 19th century, senators would work on December 24th, take the 25th off, and then come back to work on the 26th," he said. "So the idea of Christmas recess wasn't really common until after the 1850s, when trains were available."
In essence, the Christmas break got built into the system as trains became more prevalent.
In one notable case, Ritchie said, Congress fought a president's push to stay in session.
"In 1932, President [Herbert] Hoover tried to talk Congress into spending their Christmas break [in Washington] because he felt that there were a lot of Depression-era needs. And the Congress said, 'Well, we waited for a whole year for you to call us into a special session and wouldn't do it, so we're going to take our vacation.' "