Byline: Daniel Stone and Michael Picon

These post-election periods are traditionally most controversial in times like this, when a party is on deadline to cede the majority (in one, if not both, chambers). And with everything on Congress's docket this month and next--tax cuts, "don't ask, don't tell," a nuclear-arms treaty with Russia--some historians say 2010 could be among the most eventful lame-duck sessions. An unscientific assessment of others of great consequence:

1800 President John Adams

House* Jeffersonian Republicans, +22; Federalists, -22

An indecisive Electoral College vote left the choice of president to the House. Alexander Hamilton, a Federalist, worked his allies to approve Thomas Jefferson (instead of rival Aaron Burr). After days of backroom dealmaking, the outgoing Federalist majority voted Jefferson--a Jeffersonian Republican, but considered the more benign of two "bad" candidates--the third president.

1860

President James Buchanan

House* Democrats,-39; GOP, -8

Republicans lost seats the year one of their own, Abraham Lincoln, won the presidency--but Democrats lost more (both to a third party), which gave Republicans a controlling majority. That's when things got interesting: Southern Democrats from six states walked out of the session, a move widely seen by historians as the starting point of the Civil War.

1874

President Ulysses S. Grant

House* GOP, -96; Democrats, +94

The biggest congressional shake-up in history occurred when Republicans lost almost 100 House seats to Democrats. …