"This has really been a remarkable race to the finish line for the Democratic Congress," Binder said. "Democrats in both chambers see the window closing on a wide range of Democratic initiatives. … The prospect of sharing the gavel with Republicans seems to have motivated Democrats to keep up a relentless push to the end – knowing that many of these legislative efforts would be dead on arrival in the new Congress."
So is this the most productive lame-duck session in history?
"I think actually you could make the case that this is the most productive lame duck even without START," said Norm Ornstein, a congressional scholar at the American Enterprise Institute, who called the string of bills a "smashing set of achievements, whether you like them or don't like them."
"There have been lame ducks that have been aimed at just doing one thing, often just getting a budget through, or something like the impeachment of a president, but there haven't really been any that has had the breadth of this one," he added.
Other analysts say not so fast. While this year's session is undoubtedly far better than lame ducks like the session in 1948 that ended in less than two hours, there have been a few other sessions that featured their own notable accomplishments.
The 1974 lame duck, for instance, featured Nelson Rockefeller's appointment as vice president, the passage of a landmark trade act, and the enactment of a slew of major energy and environmental laws. The 1980 lame duck saw the passage of the Alaska Lands bill, the biggest land preservation bill in history. And the 1998 session will be remembered for the House voting to impeach President Bill Clinton.
"Lame ducks have brought us major trade laws, environmental programs, and presidential impeachments," said Binder, "but I'd say that it's been a remarkably productive session given how intensely the parties disagree over many of the major issues of the day."
Emotions have run high throughout the lame duck.
McConnell broke down in tears on the Senate floor as he bid farewell to his departing colleague Sen. Judd Gregg, (R-N.H.) Reid launched into an angry war of words with Sen. Jon Kyl, (R-Ariz.), about the meaning of Christmas. Sen. Bernie Sanders, (I-Vt.), protested the tax deal in an 8 ½ hour tirade on the chamber's floor.
And it's also been, at times, the theater of the absurd.
The Senate held a rare impeachment trial to impeach a federal judge, only the eighth time in history that has ever happened. Republican senators threatened to force a 50-hour oral reading on the Senate floor of the 1,924-page omnibus bill. And as Christmas approached, one Democratic senator even missed two crucial votes to attend a holiday party.