The Senate is about to embark on what could be the showdown of the year as top Democrats work to push through sweeping health care legislation.

The legislative chamber, however, is no stranger to history-changing debate. Lawmakers need to look no further than their predecessors to see how it's done.

In 1991, Congress voted for the use of military force towards Iraq after the Saddam Hussein-led country went to war with Kuwait.

The action was the first time Congress voted for going to war since the Gulf of Tonkin resolution in 1964, which officially began U.S. involvement in the Vietnam War.

Lewis Gould, author of "The Most Exclusive Club: A History of the Modern United States Senate," says one of the most contentious debates in Senate history happened in 1964.

The Civil Rights Act of 1964 is often considered one of Congress' most influential pieces of legislation. The act banned discrimination based on race, color, religion, sex or national origin, among other things.

President Andrew Johnson is often noted as most famous for being the first U.S. president to be impeached.

Johnson, who became president in 1865 after the death of Abraham Lincoln, implemented Reconstruction policies for the South -- policies that the Library of Congress notes "clashed with the wishes of a majority of the Congress, controlled by Radical Republicans who favored much stronger action. Over the next three years, Johnson and Congress were locked in battle."