WASHINGTON (AP) — Republican Jeb Bush and Democrat Hillary Rodham Clinton are asking donors to write the checks to get their campaigns started. Yet these "new" candidates have been fueling their presidential ambitions for months — years, in Clinton's case — thanks to outside groups that will continue serving as big-money bank accounts throughout the race.

In the 2016 presidential field, creative financing abounds.

While donors can give a maximum $2,700 apiece per election to their favorite candidatdte's campaign, the presidential contenders offer generous supporters plenty of other options. Outside groups that can accept checks of unlimited size include personalized super PACs that, while barred from directly coordinating with candidates, are often filled with their trusted friends. There are also "dark money" nonprofit policy groups that keep contributors' names secret.

Super PACs working exclusively to help individual presidential candidates appeared on the scene in the last race, with Restore Our Future supporting Republican nominee Mitt Romney and Priorities USA boosting President Barack Obama. One 2012 super PAC, funded almost entirely by Las Vegas casino billionaire Sheldon Adelson, kept Newt Gingrich afloat in the Republican nomination contest by spending millions of dollars on television ads promoting him and attacking other candidates.

This time, the influence of those kinds of groups will increase "by a huge factor," said Spencer Zwick, the chief fundraiser for Romney.

"Super PACs in 2012 were still not talked about by the campaign apparatus," he said. Not so in 2016. "You literally have the same leadership group that's running a super PAC that will then run the campaign, or vice versa."

Federal Election Commission Chairwoman Ann Ravel called it a Wild West atmosphere, fostered by the 2010 Supreme Court decision in the Citizens United case that empowered outside groups to take in and spend unlimited sums. She argues this system is insufficiently policed by her politically deadlocked agency.

The campaign finance watchdog group Democracy 21 has filed complaints against many of the candidates working with super PACs. Its president, Fred Wertheimer, sees "all sorts of edgy, and I would say illegal, coordination going on."

Others see no cause for alarm. "What could be more American?" asked David Keating, director of the Center for Competitive Politics, which advocates for an end to campaign contribution limits. "More money means more speech. It ensures a robust debate about the future of our country and keeps people interested and involved."

The cash flood has already resulted in more than $1 million in negative ads, according to the Center for Responsive Politics, in an election still more than 500 days away. This presidential race, with the most aggressive use yet of outside groups, is on track to cost more than the $2.6 billion tab for the 2012 presidential contest.

Bush's kickoff this week has come with pleas to help fill his empty campaign coffers. But the Republican former Florida governor has already spent six months raising money for Right to Rise, a super PAC that will help him compete by spending tens of millions of dollars on television ads.

Until he became a declared presidential candidate, Bush was free to fundraise for Right to Rise, and he did so with vigor. He told the group's top donors in April that they had helped raise more money in the previous 100 days than any Republican operation in modern times. Bush will now distance himself from the super PAC, leaving it in the hands of his longtime consultant Mike Murphy. "I'm going to miss him," Bush recently said about Murphy. "But from here on out, I'm not going to be talking to him."

Supporters can also contribute to Bush's separate nonprofit group called Right to Rise Policy Solutions. Such "dark-money" groups — so called because they don't reveal donors — are limited in how much election work they can do. GOP presidential candidates Rick Perry and Rick Santorum and possible candidates Bobby Jindal and John Kasich are each linked to a nonprofit.

Clinton, who became a candidate in April and is dominating the small Democratic field, is also benefiting from outside helpers. Fundraising emails last week encouraged supporters to become "launch donors" before the Saturday speech in New York City that was the first big rally of her campaign.

There are already 135,000 donors — some dating back two years — who might consider themselves her founding backers. They gave to a super PAC called Ready for Hillary, which was formed by aides in January 2013 to encourage the former first lady and secretary of state to run for president.

Clinton's campaign recently obtained the super PAC's donor list, and information on almost 4 million people who signed up with it, by swapping the information with other groups backing her.

One of those, Correct the Record, is blazing an entirely new trail — and one that some election watchdogs say is questionable — by planning to coordinate directly with the Clinton campaign. The group says it can avoid pushback from the election commission by not spending any money on paid advertisements and instead just posting its content for free on social media and websites.

Republican rival Ben Carson, a political newcomer, has gone about all this in reverse.

He started with a campaign announcement May 4, then dispatched top strategists to a still-unnamed super PAC. This approach comes with a drawback: Legally, the former campaign aides must wait 120 days before starting work at the super PAC.

"I put the campaign together, and now I'm going to put the super PAC together because I have the big-money contacts," said Terry Giles, who served as Carson's top strategist and will run the super PAC once he can legally do so in September. "I hired all of the campaign people, and I know exactly what their strategy is, so I can very effectively lead the super PAC. It's unorthodox from a political standpoint, but it is not at all unorthodox from a business standpoint."

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Associated Press writer Thomas Beaumont in Tallin, Estonia, contributed to this report.