With the Iowa caucuses now just a week away(!), here’s an explainer on why Iowa gets to go first and a guide to how the process will work on Jan. 3.

Why Iowa goes first: Before 1972, the Iowa caucuses received little attention. They occured in the middle of the nominating process and didn’t elect many delegates.

After the chaotic 1968 election, new national party rules led Democrats in Iowa to implement a proportional representation system, giving more candidates room to compete in the state.

The caucuses were moved up January not as a power play, but because the state party chairman was determined to give every delegate a copy of the rules and platform proposals. Officials determined that they would need four months to print the materials on their mimeograph machine.

South Dakota Sen. George McGovern focused intensely on Iowa that year and took in 20 percent of delegate representation. The frontrunner, Maine Sen. Edward Muskie, was tied with “uncommitted” at 35 percent. But the results countered the conventional wisdom that McGovern had no shot, and he ended up winning the nomination.

Iowa Democrats enjoyed the increased attention, and Iowa Republicans found themselves wishing they had an earlier caucus as well. The parties agreed to hold caucuses on the same January date in 1976, a practice that has continued ever since. That year Georgia Gov. Jimmy Carter came in second to “undecided” in Iowa and went on to win the nomination, cementing the state’s importance.

* How it works: Voters gather by precinct at 7 P.M. on caucus night. In both sets of caucuses, delegates to the county convention are allocated proportionally according to the number of supporters each candidate gets.

In the Republican process, everyone votes by secret ballot. (The Democratic process is more complicated.) There can be appeals from candidates’ supporters before the vote, but there is no negotiation or candidate-switching once the balloting begins.

Voters must be registered Republicans, but non-Republicans can register on site — creating a bit of an x-factor when trying to determine who will vote and in what numbers.

Caucus locations change every election. There are 1,774 precincts in this year’s GOP caucuses — some rural locations will get only a handful of participants while more urban precincts will likely have thousands.

What it means: In the grand scheme of things, Iowa is almost never determinative. Since 1972, only three non-incumbent candidates won the Iowa caucuses and went on to win the presidency — Carter, George W. Bush, and President Obama.

The caucuses are seen less as a predictor of the eventual nominee than as a contest that winnows the field. Conventional wisdom has it that there are three tickets out of Iowa — “first-class, coach, and standby.” Anyone who competes in Iowa but comes in fourth place or lower will have a hard time recovering, the argument goes.

Should Iowa be first? That depends on who you ask. Critics of the Iowa process say that the arcane rules and long meetings deter voters who cannot spend so much time on the political process due to financial, family or physical concerns.

Overall Iowa primary turnout is usually around six percent of eligible adults. Although it shot up to 16 percent in the 2008 cycle, that still puts it below most states. (If you look just at registered voters, it’s a little better — 19.4 percent of registered Republicans participated in 2008.)

The state is also not all that representative of the country at large, Iowa critics note. Only 17 percent of the country lives in rural areas; over 40 percent of Iowans do. The state is 91 percent white, compared to 72 percent of the rest of the country.

On the other hand, according to professor Michael Lewis-Beck of the University of Iowa, the state is extremely representative when it comes to economic factors — average pay, per capita income, unemployment, home ownership etc.

Supporters also argue that the small size of the state and the (now, relatively) long first-in-the-nation tradition has created an unusually committed and thoughtful electorate ready to vet the candidates, and that the caucus system encourages meaningful participation.

Will it change? No candidate wants to risk offending Iowa by siding with states that want to shake up the calendar. And so Iowa’s standing has withstood challenges to its primacy for decades now.

Individual candidates have boycotted: Sen. John McCain (R-Ariz.) skipped Iowa in 2000 and 2008, and former Utah governor Jon Huntsman is not competing there this cycle.

Some speculate that a victory by Rep. Ron Paul (R-Texas), whose views diverge from the GOP on many major issues, would damage the caucuses’ credibility. And there is talk that the calendar could be headed for a major shakeup before 2016. Of course, Iowa has heard it all before — and still stands at the front of the nominating process.