Explore the history, the process and the influence that the Iowa caucus has on the nation.

In the make-or-break, rough-and-tumble of party politics and the candidate selection process that culminates with the national nominating conventions, Iowa's caucuses have been an also-ran for most of the state's history.

With the exception of a one-time experiment with a primary early in the century, Iowa has always had caucuses; but they fell in the middle of the season, they didn't produce that many delegates, and for many decades party leaders in Iowa, as elsewhere, controlled the process. Presidential candidates might show up during the general election, but none of them came courting during the caucuses.

That, of course, has changed. In the last decades, Iowa has become a king maker.

This is where it all began. The 1968 Democratic Convention in Chicago where frustration with a system controlled from the top down resulted in conflict in the convention hall and riots in the streets. Chicago was the proverbial last straw, and the breakdown ensured there would be national reforms in the Democratic Party.

Larsen: "It was just terrible. We were all committed; this was never going to happen again."

In 1970 Cliff Larsen became chairman of the Iowa Democratic Party.

Caucus Leader: "So when the Senator McGovern people come over here in this corner, these people will have to move out."

When the 1972 caucuses were held, Iowa's reforms were in place, reforms that radically changed presidential politics in the state.

Caucus Leader: "Senator Muskie over here ..."

For starters, mandatory proportional representation for candidates replaced the winner-takes-all option. That may have been more fair. Equally important, it gave the press the kind of numbers it needs to call a horse race.

In addition, the reforms dictated that the caucuses be held very early. District conventions were held separately from the state convention, adding another step to the process. And the party assured that what happened at the grassroots level, from delegate selection to the party platform, made it to the next level: that is, from precinct caucus to county, district, and state conventions.

That meant time was needed for meetings and sending masses of printed material to thousands of people involved in the process. Consequently, the caucuses had to be moved back earlier and earlier.

Larsen: "We knew that we were going to be first or one of the first after we thought about it. As I always say, we had a slow mimeograph machine, but we weren't stupid. We knew we were going to be early in the process. We thought that was all right, but when the press, the national press showed up, we were totally amazed."

By 1976, it wasn't just Democrats. For the first time ever, both parties decided to hold their caucuses on the same night. In addition, the Republicans experimented with a straw poll, so the press would have some sort of numbers on which to hang a story.

1976 Reporter: "And we've got about 5 percent of the Democrats, and Carter is wiping them out."

Still, it was the Democrats that garnered the most press attention, with a little help from the party. Between 1973 and 1977, Tom Whitney was chair of the Democratic Party.

Whitney: "Basically after the ‘74 elections, we organized a very, very significant kind of effort to convince first the candidates that they ought to be in Iowa because the national press was going to be here, and then to convince the national press that they should be in Iowa because the candidates were going to be here."

Jimmy Carter: "I'm really glad to be back in Iowa."

The result of 1976 was that Jimmy Who became Jimmy Carter. And ever since then, most candidates have tried to follow in his footsteps.

Since the 1970s, Iowa, with its first-in-the-nation caucuses, has become the place where the field of candidates is narrowed.

In 1988, both parties had large fields of candidates, and caucus attendance broke records. The growth of conservative and evangelical strength in the Republican Party was underlined by the surprising second-place caucus finish of Pat Robertson of Christian broadcasting fame, putting him temporarily in front of third place finisher Vice President George H.W. Bush.

The 1992 caucuses were essentially nonevents. Incumbent Republican President George H.W. Bush was unopposed. And the candidacy of Iowa "favorite son" Tom Harkin encouraged the rest of the democratic field to bypass Iowa.

In 1996, nine Republican contenders campaigned hard in Iowa. Kansas Senator Robert Dole was the early frontrunner and ended up the party's candidate.

In 2000, Democratic Vice President Al Gore held off a challenge from Senator Bill Bradley, to win the Iowa and national nominations. Texas Governor George W. Bush beat a large field to win the Republican Iowa caucus and go on to the Presidency.

In 2004, Democratic front-runner Howard Dean finished a surprising third in the caucuses, and screamed his way out of the campaign. Also that year, Dick Gephardt conceded after his 4th place finish. Surprise winners John Kerry and John Edwards went on to become the national candidates.