One month ago, at the end of yet another day of town hall meetings sponsored by a supportive super PAC, Gov. Bobby Jindal (R-La.) told The Washington Post his strategy to break out. In three words: Iowa, Iowa, Iowa.

"We'll win Iowa, and I think the race will change," Jindal said on Oct. 13 after a Cedar Falls, Iowa, town hall meeting. "A lot of candidates will drop out. We'll get more focus on the candidates who are left."

On Tuesday, Jindal became the third major Republican candidate (and fourth overall) to quit the 2016 race. In defeat he joined former Texas governor Rick Perry and Gov. Scott Walker (R-Wis.), both of whom had once led Iowa polling -- Perry in his disastrous 2012 race, Walker just this summer. And the three of them worked Iowa hard, spending 74 (Jindal), 41 (Perry), and 22 (Walker) days campaigning across the state.

Their hard landings challenged two operating theories of 2016 politics. One was the primacy of hand-to-hand Iowa campaigning; the other was the power of super PACs to keep struggling campaigns afloat. Going into the summer, even as Donald Trump vacuumed up media attention, a combination of those factors was supposed to keep "serious" candidates competitive. Three times, that combination failed.

"Not everybody gets to do a Jimmy Carter in Iowa," said David Yepsen, the longtime Iowa political-reporter-turned-academic, referring to the first candidate to use the state's caucuses to break out. "In that sense, the failures of these candidates proves how the process works. There's a winnowing process, and there’s a limit to what money can do in a congested state like Iowa."

But in order to win the 1976 caucuses, Carter spent just 19 days in the state -- less than any of the star Republicans who have dropped out this cycle. George H.W. Bush, who repeated Carter's strategy and made the county-by-county grind a campaign tradition, spent 27 days campaigning in Iowa in the lead-up to the 1980 caucuses.

In this cycle, the candidates who've worked Iowa the hardest have struggled as the candidates running more strategic drop-in campaigns have thrived. For the first time, two former winners of the caucuses, former Pennsylvania senator Rick Santorum and former Arkansas governor Mike Huckabee, are competing for a repeat. Both are in the doldrums, with the last RealClearPolitics average putting them at 2.8 percent and 0.8 percent respectively -- behind Jindal.

That's left the campaigns arguing that working Iowa hard will eventually pay off, as it always does. "The person who comes in on a shiny bus with all the pomp and circumstance is rarely standing there victorious on caucus night," said Huckabee's spokesman Hogan Gidley, who served that function in 2008 and a similar role for Santorum in 2012. "The people who win are going to meet anybody, talk to anybody – these polls aren’t reflective of anything happening on the ground."

But Jindal, Perry, and Walker all hit a wall despite the time spent on the ground. All of them quit with substantial money still left in their super PACs. Perry's Opportunity and Freedom PAC had at least $13 million in the bank when his campaign ended. Walker's allied PACs had raised twice as much. The pro-Jindal Believe Again PAC raised a comparatively puny $3.7 million, but that was three times what his actual campaign pulled together.

Brad Todd, the primary consultant for Believe Again, said that the lesson was that campaign finance rules were too "punitive" to campaigns themselves. "The $2,700 limit is incredibly constraining," he said. "We allow people to take $2,700 to run in a congressional district that includes only Little Rock or only Syracuse. Yet we expect people to be able to run for president with those same limits."

By the next election cycle, lawsuits and conservative legislation might open up campaign accounts to more donations. In this one, the candidates counting on one state to bail them out -- and for a super PAC to make that possible -- have come up empty.