Washington (CNN) -- 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.
The Senate vote in 1991, however, was much closer than the vote over Vietnam, illustrating a deep divide over whether to get involved.
Historians note that the White House had serious concerns over the fierce debate in the Senate and whether the White House would have to go to war without Congress' approval.
In the end, the Democratically controlled Senate approved the resolution 52 to 47.
Senate Historian Donald Ritchie says the Persian Gulf War debate was notable in that each senator felt the need to have his or her voice heard.
"I think it was a major foreign policy issue that every senator felt they needed to go on record and take a side. It was a very serious debate and a very somber debate at the time ... every vote was a critical vote so everybody had to justify where they were taking a stand," Ritchie says.
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.
While the bill was intended to protect black Americans, it ultimately increased civil rights protection to all -- focusing heavily on women's rights in the workplace.
But the bill was met with heavy opposition, especially from Southern Democrats, otherwise known as Dixiecrats, as well as segregationists. The group tried to kill the bill with a filibuster, but there was enough Republican support to end the filibuster.
The passion behind the argument, Ritchie notes, came because there was a major social change occurring in America.
"There was a sense that you couldn't do it fast -- you had to show that everybody [senators] got to be heard and that all of the issues were raised," he said. "I think the length of the debate helped to make the civil rights act more acceptable across the country and there was less resistance to it, perhaps, because the nation had watched the debate go on as long as it had."
In the end, the Civil Rights Act passed with overwhelming support.
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."
The official legal basis for the impeachment was the Tenure of Office Act. It was passed over Johnson's veto on March 2, 1867.
"It forbade the president to remove civil officers appointed with the consent of the Senate without the approval of the Senate," according to the Library of Congress' Web site. "Despite the certain consequences, Johnson decided to remove Secretary of War Edwin Stanton, an ally of the Radical Republicans. This act enraged Johnson's political enemies and set in motion the first presidential impeachment."
Johnson's Senate trial began on March 5, 1868. After realizing they did not have the necessary two-thirds majority vote to impeach, Republicans adjourned the trial. That essentially ended Johnson's impeachment procedure.
In the 1990s, President Bill Clinton would face a similar onslaught of criticism from Republicans looking to impeach him over the Monica Lewinsky scandal. He, like Johnson, was ultimately vindicated.
Frances Lee, a political scientist at the University of Maryland, says many of the greatest Senate debates were over foreign policy.
In 1919, that foreign policy issue was the Treaty of Versailles, which ended World War I and created the League of Nations.
President Woodrow Wilson, a staunch advocate for the League, put the treaty to the Senate in hopes he could get enough votes for it to be ratified.
But the League was met with heavy resistance in the Senate.
Republican Sen. Henry Cabot Lodge, chairman of the Foreign Relations Committee, was a fierce opponent of the Treaty of Versailles. He fought against it with full might in the Republican-dominated Senate.
Historians note that Lodge's main concern was that the Treaty represented and end to American sovereignty, a view that pitted him against Wilson's foreign-policy philosophy.
Hearings were held in the Foreign Relations Committee for months, and a debate later came before the full Senate on September 16.
But negotiations hit a major roadblock. After nearly 60 days of debate, the Senate rejected the treaty.
Ritchie notes that historians opined that Wilson made a big mistake in not inviting Lodge to go to Paris with him to negotiate the treaty.
"The Senate had no stake in the treaty -- it was Wilson's treaty, and therefore it became a political issue" he added.
The Compromise of 1850 involved the passing of five laws focusing on slavery.
Burdett Loomis, a professor of political science at the University of Kansas, says the series of debates on slavery might be "dramatic and important as any in our history."
"Given that these started at the constitutional convention, and lasted until 1860, their scope is overwhelming."
In 1849, California requested permission to enter the Union as a free state, which had the potential, most historians argue, to upset the balance between free and slave states in the United States.
Sen. Henry Clay introduced resolutions on January 29, 1850, in an attempt to seek a compromise and avert a crisis between North and South.
Three of the Senate's greatest statesman -- Henry Clay, John Calhoun and Daniel Webster -- took part in many of the contentious debates, according to Burdett.
"The emphasis was wholly on Northern aggression and against the trend for conciliation and compromise. Calhoun would return to the Senate on March 7 to listen to the speech given by Daniel Webster in favor of Clay's resolutions, but died shortly after, on March 31, 1850," according to the Library of Congress.
Loomis argues, though, that their debates failed to sway the Senate because "in the end, the words could not stop the (Civil) war."