Are you afraid of the dark?

It might seem like a silly question, but once in your life you probably wondered what evil things lurked in the shadows. And no matter how much grownups assured you there was nothing there, it was obvious that adults had spent a lot of energy and a lot of time inventing things to push the dark back into the corners.

Darkness is not just a thing of our childhood superstitions. Now we're told that science has its dark spots too. Dark matter and dark energy – these are terms we use to fill in the gaps for the effects we can see or measure, even though the causes are still unknown.

Likewise politics has its own dark forces, and they're far more real than anything you feared as a kid.

It's called dark money, and it's how secret donors get their funds to political candidates and causes without you knowing about it.

One of these you might be familiar with, already. They're called political action committees, or PACs. Initially, they were a way for lots of people with similar interests to pool their resources together and affect political change.

But there was a more sinister use for PACs.

Sometimes a particular donor might be unpopular with one group of voters or another – their own political boogey man. And it would be suicide for a candidate to accept money from them directly.

So politicians and their benefactors invented a system called PAC-to-PAC contributions.

It worked like this. First, a donor would direct their contributions to several different PACs. Often those PACs had names that had no relationship whatsoever with their contributor's intentions. A polluter could contribute to an environmental PAC, or a union could give to a business PAC.

And at the same time one donor made contributions to those PACs, others were doing the same – some of them you might consider politically nefarious, others completely harmless.

From there, the consultants who controlled those PACs would shuffle the money between them in a never-ending shell game. The cash -- at least on paper -- would become what accountants call "fungible," meaning it was all basically one indistinguishable pool and impossible to trace to its source.

If this seems like money laundering, that's kind of the point. Candidates could take cash from unpopular donors and no one would be the wiser but them.

You might have noticed that I've been using the past tense. That's because in 2010, something happened. In Alabama, a Republican majority took control of the legislature and, in one of its first acts, it banned PAC-to- PAC transfers.

So did everyone live happily ever after?

Hardly.

Something even darker took the place of PACs. They're non-profits called 501(c)4s, and their effect on campaign finance transparency is growing.

Under IRS rules, 501(c)4s were meant to exclusively promote the social welfare. But we're not talking about money for poor people. You see, because the IRS interpreted exclusively to mean primarily, these non-profits have become a conduit for political action and campaign cash.

And since then, in recent years, the IRS has been so lax about policing these non-profits, exclusively has all but come to mean – umm -- some.

In practice, 501(c)4s work similar to PACs. They have names that can conceal their real purpose. Donors put money in, and the non-profits push money out.

A 501(c)4 can't fund a candidate directly, but it can buy advertising that criticizes a candidate on a particular issue, or promotes a candidate's record on another.

Also, their lobbying power is unlimited.

But there's one major difference between 501(c)4s and PACs. Unlike PACs, 501(c)4s can keep their donors completely secret. Whoever is pumping money into them is impossible to see -- meaning that candidate you vote for at the ballot box might have received help from someone you hate, and there's no way for you or anyone else to tell.

It's all hidden -- in the dark.

Are you afraid of the dark?

If you weren't before, maybe now you should be.