Iowans want to be inspired. Photo: Joe Raedle/Getty Images

Among the vast compendium of lore thrown into political discourse by the Iowa Caucuses over the last 40 years or so is this famous slogan from former Democratic congressman Dave Nagle:

There are three rules to success in Iowa … Rule No. 1 is: Organize. Rule No. 2 is: Organize. Rule No. 3 is: You get hot at the end.

This last part about the value of peaking at the right moment is good advice for the candidates forming the Big Four in recent polls of likely caucusgoers (Pete Buttigieg, Elizabeth Warren, Bernie Sanders, and Joe Biden) and for those bottom-feeders thought by some to have a chance of coming from the back of the pack down the home stretch (notably Amy Klobuchar). But simple as Nagle’s three rules are, recent Caucus history is a little more complicated than that, since the “end” at which you need to get “hot” is defined in different ways by different people. Katie Akin of the Des Moines Register offers a useful rundown on the path to victory on Caucus Night of various recent winning candidates in both parties:

Hillary Clinton stayed at the top of 2015 and 2016 Iowa polls, as rival Bernie Sanders climbed steadily closer. The final poll before the caucus had Clinton just 3 points above Sanders, 45 percent to 42 percent. Ted Cruz surged in December, taking first place with 31 percent. No November poll was conducted in 2016. Cruz lost his polling lead in a late-January poll as Donald Trump climbed, but more votes went to Cruz on caucus night. Rick Santorum was tied for sixth place in November 2011. He shot up in the December poll to 15 percent, though he still lagged behind leaders Ron Paul and Mitt Romney. The late momentum carried through caucus night, when he was virtually tied with Romney for first place — and later declared the winner. Mike Huckabee surged in the late November 2007 Iowa poll from third place, with 12 percent, to first place, with 29 percent. The poll was published in early December, one month before Huckabee won the caucus with 34.4 percent of the vote. Barack Obama led the Iowa poll for the first time in November 2007, with 26 percent of the respondents marking him as their first choice. He widened his lead over opponents Hillary Clinton and John Edwards in the late-December poll, ultimately winning the caucuses by a nearly 8-point margin. John Kerry was third place in November 2003, behind Democratic leaders Howard Dean and Dick Gephardt. He leaped to first in a January 2004 poll, from 15 percent to 26 percent, then won the caucus.

These outcomes may not have as much in common as you’d think, aside from winning candidates finishing strong — which of course they did!

HRC won in a tough grind against one other well-organized candidate in a race that had steadily grown closer as Caucus Night approached (She led Bernie Sanders in the RealClearPolitics polling averages by about 13 points on January 1, by only by 4 points on the eve of the vote). Cruz maintained an organization far superior to Trump’s, which made his close second in late polls enough for a win. Santorum spent more time in the state than any other 2012 GOP candidate, and benefited from hard-core ideological voters and the late collapse of support for paper tiger front-runner Newt Gingrich. Huckabee was perfectly positioned for Iowa’s social-conservative-heavy Republican activists, and was helped by ultimate nominee John McCain’s refusal to go all in. Barack Obama won by expanding the universe of caucusgoers to include a lot of young voters and independents. And John Kerry successfully did what Kamala Harris has tried to do this year, all but abandoning other states in order to pull off a late Iowa surge.

Nobody in either party has won Iowa without a solid organization and momentum, but the exact timing of when a candidate “surges” has varied. This question is of particular importance to Pete Buttigieg, whose surge in the November Register/CNN/Mediacom Iowa poll resembles that of three recent winners: Cruz, Huckabee, and Obama.

But in that poll, 62 percent of respondents said they could still be persuaded to change candidates before Caucus Night. That should make Team Pete — and any subsequent Iowa front-runners — nervous.