Since 1972, only three Republicans and five Democrats have won both Iowa and their respective political party's nomination. But given the event's history, Donald Trump's may not be the GOP nominee after all.

Iowans in 99 counties will caucus in each of the state's 1,681 precincts on Monday night in a presidential nomination ritual that dates back 44 years. A scheduling snafu in 1972 forced Iowa's Democratic Party to move their caucus weeks ahead of the New Hampshire primary, in essence giving the state "first-in-the-nation" voting status well before the process became pivotal to White House hopefuls.

The switch gave relatively unknown Southern governor named Jimmy Carter a leg up on incumbent Republican President Gerald Ford. Carter narrowly won the general election, primarily on unprecedented media coverage that began with the grassroots caucuses. Since, Iowa has grown into the election season's jumping-off point, one where GOP and Democratic candidates alike test the waters for a presidential run.

Some withstand poor Iowa showings to win their party's nomination. Others flame out, despite country-wide notoriety and high finances.

George H.W. Bush placed third among Republicans in 1988 and won the presidency; Bill Clinton became 42nd president after finishing fourth among Democrats in 1992. Conversely, Mike Huckabee won the Republican Iowa caucuses in 2008 but lost to John McCain, who finished fourth with just 13 percent. George W. Bush was the last Republican to win both, doing so in 2000.

The Process

There isn't much science behind Iowa caucuses. Unlike general elections, caucusgoers don't walk into voting booth; they commune with fellow Democrats or Republicans and choose delegates in two very different ways.

Republican voters listen to the meeting's attendees promote their candidate before scribbling their nominee's name on a piece of paper and dropping it in a box.

Democrats split up depending on the delegate they favor. They listen to each side's argument, switching groups until one has less than 15 percent of the room's support. People within the group of 15 percent then choose whether to support another candidate or sit out altogether.

The process of elimination continues until 44 Democratic and 30 Republican delegates are selected for each party's national convention in the summer.

The problem is that there's no credible way of tracking who Iowans will vote for beforehand. Months of candidates' stump speeches, campaign stops and intimate town hall get-togethers can be rendered meaningless with a slip of the tongue.

2016 Iowa Caucuses

According to the latest Public Policy Polling (PPP) survey released Jan. 28, at least 31 percent of likely Republican caucus-goers say they can still change their minds.

GOP front-runner Trump carries an eight-point advantage of Texas Sen. Ted Cruz, but public opinion may change in light of Trump's decision to bow out of the Des Moines Republican debate.

"Currently 31 [percent] of the likely electorate is supporting someone among the also rans - the 9 candidates in single digits," read a PPP statement. "But 43 [percent] of those voters are open to the possibility of changing their minds - possibly casting a strategic vote."

"And among that group supporting the also rans 35 [percent] say they would pick (Florida Sen. Marco) Rubio, 25 [percent] say they would pick Cruz, and 17 [percent] say they would pic Trump if they had to choose between leading contenders."

Much like Carter, Bush Sr., Clinton and McCain, whoever loses may be better off. Since 1972, only three Republicans and five Democrats have won Iowa and their Party's nomination.

Every candidate heading into Feb. 1 caucuses believes they have something to gain. By Tuesday morning -- more often than not -- reality sets in that they've already lost, regardless of what early poll numbers may say.