KNOXVILLE, Iowa — It isn't until his seventh stop, almost two hours into his work on an icy Sunday afternoon, that James Ahn hits pay dirt, in the form of Jennie and Arvin Van Waardhuizen.

Until recently, Ahn, a 31-year-old Columbia law school graduate, was working for a posh Boston law firm, structuring complex investment deals for venture capital funds. Today, computer printout in hand, he is trudging from house to house, seeking to explain to potential Hillary Clinton supporters a process that seems nearly as arcane: how to participate in the Iowa caucuses.

The Iowa ground game is a game of centimeters. The universe of known caucusgoers is small and hotly contested: Just 122,000 Iowans participated in the 2004 Democratic caucuses. The victor this year will be the candidate who can lure more of those proven caucusgoers, or the one who succeeds in expanding the pool with new entrants.

This is where James Ahn comes in. The people on his printout have already been identified as Clinton prospects; his job is to seal the deal with these folks, who've never caucused before or haven't gone in years.

So after a series of fruitless knocks at empty homes, after talking fast through a barely opened door to a woman whose commitment to Clinton — or to caucusing, for that matter — seems doubtful, Ahn has finally made it into the Van Waardhuizens' cozy living room, where Santa figurines line the mantel.

Within minutes, Ahn has given his basic, don't-let-the-process-scare-you spiel: Get there by 7, stand in Clinton's corner, make sure you're counted. He has jotted down that Arvin wants to see Bill Clinton and has delivered a requested yard sign.

In a mass-media age, there is something charmingly anachronistic about the small-town way presidential politics is practiced here. Iowa and New Hampshire are valuable in preserving the ability of voters, at least some voters, to get to know candidates as more than flickering images on a screen or talking heads in a televised debate.

"This is our third follow-up visit since Hillary's come to town," says Jennie Van Waardhuizen, 55, who runs her parents' small manufacturing plant. "I got an e-mail from Hillary," offers Arvin, 60, an Air Force veteran.

And yet, to join Ahn on his appointed rounds is also to reinforce doubts about a system of irrationality layered on irrationality. The caucuses draw a small, unrepresentative sample of a small, unrepresentative state. While nearly 30 percent of eligible voters participated in the 2004 New Hampshire primary, just 6 percent went to the Iowa caucuses, according to data compiled by George Mason University professor Michael McDonald. The 2000 turnout figures were even more skewed, 44 percent in New Hampshire compared with 7 percent in Iowa.

This year's outreach may boost those numbers, but most Iowans view the caucuses as an obscure art practiced by an elect few. "Usually I don't go, because I'm afraid I'm going to get there and feel like a dummy," one man on Ahn's list confides.

"That's what I need to find out more about — I don't know how to go to caucus," says Sherilyn Orr, 64, who eagerly accepts a refrigerator magnet printed with the caucus date. Candidates spend enormous sums — it could be as high as $20 million — to win this handful of votes. John Norris, the organizing guru who helped propel John Kerry to his 2004 victory here and is advising Obama, estimates that the top candidates will spend around $400 per caucus vote.

All for a result whose significance resides largely in the fact that it is deemed significant. Political reporters, myself included, get misty over the notion of neighbors gathering on a cold winter night to hash out differences over who is the best candidate. But the caucus process also serves to disenfranchise — those who would rather not state preferences publicly or those who can't make it at the assigned hour. In the course of our afternoon together, Ahn knocks on the door of one woman who says she can't make it because she's just lost her husband; a few other people say they're scheduled to work that night.

The bizarre rules of the Democratic contest further distort the results. (Republicans employ a more straightforward method: The candidate with the most votes wins.) Why should a candidate who fails to meet the 15 percent threshold of viability walk away empty-handed? Why should the final outcome depend on how those losing campaigns decide where to throw their backing when, in caucus-speak, nonviable preference groups realign for a second round? No wonder the caucus process makes ordinary people's heads hurt.

Why should some votes — in precincts that had a good turnout in the last election, in rural areas — get more weight than others? Why aren't the raw numbers — how many voters supported which candidates — made available?

And perhaps the most important question: Given all this, why do we in the media invest the caucuses with such make-or-break significance?

Ruth Marcus is a member of The Washington Post's editorial page staff.