Three super PACs supporting former Texas governor Rick Perry are expanding their efforts as his campaign had run low on cash. (David Goldman/AP)

If this were any other election cycle, Rick Perry would have reached the end of his presidential bid this week when his campaign nearly ran out of cash.

But this is a new era, when a wealthy rancher friend of Perry’s could wake up Tuesday morning, read news reports that the former Texas governor’s campaign was no longer able to pay its staff and dash off a $100,000 check to one of the Republican’s allied super PACs.

Perry’s White House hopes will now live on a little longer, as a result of a trio of cash-rich independent groups that quickly jumped in to backfill his campaign as it pares down.

“We saw this coming,” said Austin Barbour, senior adviser to the Opportunity and Freedom PACs, which have begun building their own field operation in Iowa — a task typically handled by campaigns. “We knew we would have to do more than just paid media and there’s nothing in the playbook that says we can’t do that.”

The pro-Perry effort is one of the most dramatic examples of the dominant role that super PACs and other outside groups are playing in the 2016 race. Emboldened by narrowly written federal rules, groups flush with money are effectively subsidizing official campaign operations — and in some cases, vastly outpacing them.

A super PAC supporting Carly Fiorina is building a field operation to support her in three early primary states. (David Goldman/AP)

A super PAC that former Florida governor Jeb Bush helped stockpile with $103 million is planning to provide the Republican candidate with major cover on the airwaves once the primaries ramp up in the spring. A Democratic super PAC is running a rapid-response operation in coordination with former secretary of state Hillary Rodham Clinton’s campaign.

Super PACs aligned with Louisiana Gov. Bobby Jindal, former Hewlett-Packard chief executive Carly Fiorina and now Perry are going even further — helping to keep alive the Republicans’ long-shot bids by investing in on-the-ground organizing and event production.

“This is a new age in national campaigns,” said Jeff Miller, Perry’s campaign manager. “There’s no doubt that Austin and his team at the super PAC are doing an unbelievable job to support our efforts.”

Super PACs — which are not supposed to work directly with the candidates they are supporting — are having the most extreme effect on the GOP side. Fifteen Republican contenders are now backed by groups that can accept unlimited money, a dynamic that will help sustain a large, tumultuous field for months.

It’s a vastly different environment than it was just four years ago, when single-candidate super PACs were still a new phenomenon and underfunded contenders such as former Minnesota governor Tim Pawlenty dropped out early in the process.

That heartens David Keating, a conservative activist who brought vs. FEC, the federal case that led to the creation of super PACs in 2010.

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If it weren’t for their well-funded outside allies, “probably a lot of these candidates wouldn’t be running, and if they were, they wouldn’t be taken seriously,” Keating said. “More choice for voters is better.”

But critics of the rising influence of wealthy donors say the deep-pocketed groups are distorting campaigns, washing out the voices of those who cannot give large amounts.

“There’s something to be said for the fact [that] if you have to collect small contributions, your money runs out when the market doesn’t support you,” said Nick Penniman, executive director of Issue One, which seeks to reduce the impact of big money on politics. “A single donor can float an otherwise unviable candidate for the length of the primary.”

In a previous cycle, Perry’s prospects would have appeared dim. With cash running low, his campaign is morphing into a skeletal operation. Staff members — who were paid only through last Friday — are now staying on as volunteers. The remaining resources will cover the candidate’s travel on commercial flights to events in the early-voting states, with the aim of getting his message out in media interviews.

But the former governor is able to lean heavily on the three Opportunity and Freedom super PACs, which together raised nearly $17 million through early July. The money largely came from three rich Texans, including $6 million from Perry’s campaign finance chairman, Kelcy Warren, a billionaire chief executive of an energy pipeline.

Other longtime Perry backers are lending support, such as a rancher near Amarillo, Tex., who sent a $100,000 check Tuesday. That’s more than 37 times the amount a donor could give the official campaign, which can accept only up to $2,700 per person for the primary contest.

“He wasn’t on our radar screen, but he tracked me down and said, ‘I want to help the governor, what can we do?’ ” Barbour said, declining to name the donor to protect him from media inquiries.

The super PACs initially planned to focus on paid television advertisements but switched gears when strategists saw that Perry’s campaign reported having just $883,913 at the end of June. Now, they’re beefing up in Iowa, where they recently hired a state director and a deputy state director.

“This field is so fluid,” Barbour said, adding, “Things can work out great for him if we just be patient.”

The expanded pro-Perry operation is being modeled in part on the super PACs backing Jindal and Fiorina, both of which have ventured into new terrain.

Jindal’s allied super PAC, called Believe Again, is organizing town-hall meetings in Iowa that the Louisiana governor is invited to as a “special guest.” The group promotes the events with postcards, robo-calls and via social media, drawing a couple of hundred voters on average.

“We just get the time and place and show up,” said Shannon Dirmann, a spokeswoman for Jindal’s campaign.

Believe Again — which has spent nearly $900,000 on TV ads in Iowa — has held 14 town-hall gatherings and hopes to hold a total of 50 this year, reaching every corner of the state. In organizing the events, the super PAC is relying on a 2011 Federal Election Commission advisory opinion that said candidates could appear as featured guests at super PAC fundraisers, said Brad Todd, the group’s strategist.

“Once we saw Jeb Bush holding a ton of super PAC events where you had to bring a check to attend, we thought, ‘Why not hold them, but only ask that people bring their opinions?’ ” he said. “We think too many super PACs previously have not taken a broad enough view in how they communicated.”

CARLY for America, the super PAC backing Fiorina, is plowing money into building field operations in Iowa, New Hampshire and South Carolina. The group has half a dozen staff members on the ground in each state who are organizing volunteers, with a focus on “high quality” in-person contacts, strategist Stephen DeMaura said.

“What we’re going to see in this race is a lot of swings and shifts in the polls, a lot of movement,” he said. “We’re trying to make sure we have enough people out there. We want to build a real organization, not just a paper tiger.”

The campaign declined to provide information about the size of its staff, but DeMaura said the super PAC probably has a bigger operation on the ground than Fiorina’s official operation.

Groups such as his are helping to fuel a competitive nomination fight, he added.

“Right now, we have a very healthy primary on the Republican side,” DeMaura said. “We have an enormous number of good candidates and I think it will play out for a while, and I think that’s a good thing.”

Campaign finance experts said that super PACs are likely to continue to dominate national campaigns, because there are few signs that a polarized Congress or FEC will try to rein them in.

“I think the tolerance for risk is going up the more that the law seems to not make much sense and there doesn’t seem to be aggressive enforcement,” said Larry Norton, a former general counsel at the FEC. “There are clearly some roles for campaign committees, but I think their role is likely to become more and more diminished over time.”

Ed O’Keefe contributed to this report.