(FOX19) - Kentucky's high profile senate battle pitting incumbent Republican Mitch McConnell against democratic challenger Alison Grimes is on pace to become the most expensive senate race in U.S. history.
That's thanks in no small part to the "dark money" pouring into the Commonwealth.
Political currency was made possible by the landmark Citizens United case of 2010. Citizens United drastically changed how political campaigns are financed and paved the way for tax-exempt organizations, known as 501(c)4s, to accept undisclosed donations made by anonymous individuals, large corporations and labor unions.
$300 million dollars in dark money was spent in 2012 alone, used to target both Democrats and Republicans and this year it's playing a factor in the race for senate in the Commonwealth.
So what exactly is a 501(c)4?
Sarah Burner, who is with the Center for Responsive Politics, a watchdog group that tracks every dollar in every election in the country, explains:
"Largely, it refers to groups, predominantly nonprofit, that don't have to disclose their donors and can spend unlimited amounts of their budget on politics and they don't have to tell the voters anything about them. They spend enormous amounts of money targeting elections," she tells FOX19.
One of the groups targeting the senate race in the Commonwealth is the Kentucky Opportunity Coalition, the 501(c)4 behind a number of recent ads targeting Alison Grimes.
According to the IRS, 501(c)4s must operate primarily to "further the common good and general welfare of the people of the community … such as by bringing about civic betterment and social improvements."
According to the Kentucky Opportunity Coalition, their primary goal is to educate citizens on what it calls: "The Obamacare Train wreck."
The coalition's Senior Advisor is Scott Jennings, who once served as Press Secretary for the GOP in Kentucky's state house and worked for Mitch McConnell during a re-election campaign. Then there's Bridget M. Bush, who sits on the board of directors at the coalition. She's an attorney who has represented Rand Paul and she founded Elephants in the Bluegrass, a conservative blog.
But there's not much more we can tell you about the coalition; thanks to the Citizens United ruling we don't know how much dark money has been raised and we can't tell you how much of it comes from big corporations, wealthy individuals, or labor unions.
One things we do know: As November approaches, more and more dark money is going to find its way into the race for Kentucky senate.
"Most campaign spending happens in the 3 months prior to the election so I would imagine this race could reach certainly unprecedented levels for Kentucky but potentially unprecedented levels for any senate race," adds Bryner.
FOX19 NOW is going to continue to follow all of the money in this race, and that includes any and all 501(c) 4s running ads in support of Alison Grimes so that you know the impact dark money is having on Kentucky's senate race.
That's the bottom line, and that's Reality Check.