It's called a lame duck session.
But, with apologies to the Marx Brothers, why a duck?
The term was first used in 18th century London to describe a stock broker who could not pay his debts .. and was thus as powerless as a lame duck.
It was first applied to American politicians in the mid 19th-century - and now commonly refers to those who've lost re-election or are not running again but are still in office - their power greatly reduced.
Originally, the Constitution required Congress to meet once a year, in December.
With elections held in November, but the new Congress not sworn-in until March, that meant a mandatory lame duck session.
That changed in 1933, when the 20th Amendment said Congress must meet -- and the new members take office -- on the same day .. January Third .. making it all just .. ducky.
That's a page from my notebook.
I'm Katie Couric, CBS News.