The Denver Post: Dark money — millions of dollars spent on political messaging across the nation that can’t be tracked to a specific donor — is playing a role in politics right here in Colorado.

Its existence in the world of campaign finance is a mockery of the idea that if you’re trying to buy an election in the U.S., everyone will at least know who you are.

For political reporters, there is nothing more frustrating than hitting the end of a follow-the-money trail at a 501(c)4.

The dreaded 501(c)4 is a nonprofit under IRS tax code, and is defined as a “social welfare” group. As nonprofits, they are not required to disclose their donors even if they are expressly advocating for a candidate.

And if a group’s mailers or TV ads don’t use the magic words of express advocacy — like “vote for this candidate” — they don’t even have to disclose what they spend.

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