Former Utah governor Jon Huntsman Jr. (R) did poorly in the Iowa caucuses in 2012, placing seventh. (He didn't actively compete in the state.) His campaign fundraising had been limping along, but he stayed on the trail. When he placed third in New Hampshire, he seemed confident. Third place, he said, was "a ticket to ride" — to South Carolina, the next primary in line.

A reporter from Mother Jones who was at Huntsman's "victory" party that night ran into Huntsman's father, Jon Huntsman Sr. "Do you think you'll continue supporting [your son] financially going forward, sir?" Andy Kroll asked. Huntsman's father demurred with a smile.

Kroll asked because Huntsman Sr. had already put millions of dollars from his sizable fortune into an outside political action committee on his son's behalf. The super PAC, Our Destiny, consistently raised two to three times as much money as Huntsman's campaign each month, largely thanks to checks from the father. But Senior didn't keep supporting Junior. After New Hampshire, there were no more big checks until after Junior dropped out of the race — which he did before South Carolina.

Huntsman wasn't the only candidate who was able to stick around in 2012 thanks to a generous outside benefactor. The more notable example might be former speaker Newt Gingrich. His campaign fundraising outpaced Huntsman's by a wide margin, but it was dwarfed by contributions from Nevada casino magnate Sheldon Adelson to a super PAC called Winning Our Future. The super PAC ended up spending $13 million supporting Gingrich — and $4 million bashing Mitt Romney — before the candidate dropped out.

Adelson's generosity was noticed at the time. The New York Times reported that Gingrich was struggling by the time New Hampshire rolled around. But then ...

... the cavalry arrived: a $5 million check from Mr. Adelson to Winning Our Future, a “super PAC” that supports Mr. Gingrich. By Monday morning, the group had reserved more than $3.4 million in advertising time in South Carolina, a huge sum in a state where the airwaves come cheap and the primary is 11 days away. The group is planning to air portions of a movie critical of Mr. Romney’s time at Bain Capital, the private equity firm he helped found.

Gingrich won South Carolina.

"Super PACs were an enormously potent factor in the primaries," said Sheila Krumholz, executive director of the Center for Responsive Politics when we reached her by phone Wednesday. "This was such a critical piece of who was viable and how long." A surge of super PAC spending allowed candidates to "remain competitive well past the point where they would otherwise."

Since 2012, outside spending has only grown more important. Last year, outside groups put more money into most key races than the candidates themselves. We speculated that campaigns could someday be entirely super PAC-run, which seems unlikely. But then, candidates for president being able to stay in the race thanks to massive outside spending probably would have seemed unlikely even five years ago.

There's little doubt that the importance of PACs (and tax-exempt 501(c)(4) groups) will expand during the 2016 election, in ways still being thought up by the lawyers working for likely presidential contenders. The change created by the Supreme Court's 2010 Citizens United decision wasn't only to expand the ways in which people and businesses could undertake political activity. It (and subsequent decisions) also established that the court was willing to consider other expansions. "Folks know that there is great latitude to try new things and push the envelope in ways they would never have dreamed of doing before Citizens United," Krumholz said. And the Federal Election Commission, led by three Democratic and three Republican commissioners, has proven to be deadlocked — staying out of a number of legally gray spending decisions.

The prospect of super PACs stepping in to keep candidates viable has a clear upside. In a system without viable third party candidates and, more importantly, with two parties that are committed to excluding a third party, candidates with less support at the outset of a campaign could be bolstered by outside spending until they gain name recognition or, perhaps, until presidential primaries later in the campaign cycle where they might do better. In the meantime, they can play the role of outsiders, challenging front runners on behalf of less politically powerful constituencies. (Assuming those PACs also help them meet the often fuzzy benchmarks set for participation in debates.)

For those who oppose the expansion of campaign spending — particularly the hard-to-track "dark money" which still finds its way into the system — the downside is obvious. One reason is that outside groups and campaigns have grown considerably more comfortable in working together, despite legal prohibitions against doing so. As we noted last week, those thinking about running for office can set up entire campaign plans with outside groups before they officially declare a candidacy. Once the actual (legal) campaign begins, the ways in which candidates and PACs work together have gotten very innovative — which comes closer and closer to eliminating the idea of campaign contribution limits entirely. "The resources that are required and desired for a run for the White House are so vast," said Krumholz, "that it's always only ever pull-out-the-stops."

In 2012, neither Huntsman or Gingrich really threatened Mitt Romney, despite the help from outside groups. In future races, candidates may become viable — and stay viable — thanks to one particularly generous benefactor. If Jon Huntsman Jr. had been doing a bit better, his father's decision-making might have been very different. As might the outcome of the race.