Who's Funding the 2016 Election? Mostly, We'll Never Know.

Dark money groups have spent $143 million on the 2016 U.S. presidential election since last July--nearly four times as much as the candidates' own campaigns, Politicoreported in a new analysis on Tuesday.

The origins of most of that funding will never be revealed, while some of it will be made public at midnight on January 31, just hours before the Iowa caucuses, writes Politico's chief investigative reporter Kenneth P. Vogel.

With federal regulators struggling to navigate the election landscape in the wake of the Supreme Court's 2010 Citizens United v. FEC decision, outside groups are having an increasingly powerful influence over the proceedings, Vogel found.

"Every day, we learn more and more about how super PACs and other outside groups are working extremely closely with federal candidates," said Federal Election Committee (FEC) member Ann Ravel.

While the Supreme Court's Citizens United decision opened the door to unlimited campaign spending by outside groups like corporations and super PACs, the blame is also shared by the FEC itself, which has been criticized for its toothless approach to regulating the flow of dark money, Ravel said.

In the intervening years since they handed down the decision, it's become clear justices "did not understand what the implications were going to be of what they did," she continued, adding that enforcing transparency and preventing coordination between candidates and their supporting groups "are the two issues that are the most frustrating, because the court was very clear about it and the law is very clear about it, but it's clear that this is not the reality in the 2016 election."

Some candidates are reaping more rewards than others. Vogel reports:

Among the most aggressive interpretations of the coordination rules is the work of [Hillary] Clinton and her big-money allies. They have pioneered a relationship in which a super PAC called Correct the Record provides research and communications assistance directly to the former secretary of state's campaign for the Democratic presidential nomination.

In addition to paying Correct the Record more than $280,000 for research through July, the Clinton campaign also coordinates its media talking points and messaging with the super PAC, which was created by Clinton antagonist-turned-enforcer David Brock. Correct the Record argues that this relationship is permissible because the coordination ban applies only to paid television and radio advertisements known as "public communication(s)" and not to communications with the news media or those with the public made through emails or the Internet, which since 2006 mostly have been exempt from FEC regulation.

According to Paul S. Ryan, an executive at the election finance watchdog group Campaign Legal Center, that tactic is a "misunderstanding of the law"--specifically, a section which defines coordination as "expenditures made by any person in cooperation, consultation, or concert, with, or at the request or suggestion of, a candidate, his authorized political committees, or their agents."

Elsewhere on the campaign trail, groups supporting Jeb Bush have reportedly spent a whopping $61 million on advertisements for the former Florida governor, culled through fundraising dinners where the candidate himself appeared--before and after declaring his run. And Marco Rubio's backers have launched a nonprofit called the Conservative Solutions Project, which has reportedly spent $9.5 million on ads for his run. The group is registered under a 501(c)(4) tax code, which allows it to hide its donors' identities.

All of the major candidates--with the exception of Bernie Sanders on the Democratic side and Donald Trump for the Republicans--has the support of at least one outside spending group dedicated to their election, Vogel said.