Senate Majority Leader Harry Reid is on a mission to convince Americans that David and Charles Koch are “shadowy billionaires” who are rigging the country’s electoral system and trying to “buy our democracy.”

They are “un-American” Reid declared in the Senate on March 26 in one of his many speeches bashing the politically active brothers. They’re “immoral” and “dishonest” according to the Nevada senator.

Reid’s attacks on the Koch brothers have been relentless in the last few weeks and he’s promising to keep them up in advance of November’s midterm elections.

Why? The Kochs aren’t running for office. But they are pouring millions of dollars into the campaigns of those who are through the conservative group they founded, Americans for Prosperity (AFP), and other political action committees (PACs).

They also give generously to a number of think-tanks and organizations that align with their views. David Koch once ran for U.S. vice-president as a member of the Libertarian Party, which gives a good indication of his views. The brothers are known as champions of the free market who advocate for lower taxes, less government regulation, and for people helping themselves rather than relying on government handouts. Their critics describe their agenda as fringe and radical and say the Tea Party and Republican conservatives have adopted many of their beliefs.

Kochs among world's richest people

A Washington Post article said so far this year AFP has spent $27 million on television advertising. About $13 million of that was directed at five Senate races while other ads criticized the Affordable Care Act.

Democrats aren’t just up against Republican candidates this fall, they’re up against the Kochs' bank accounts, and based on how the Democrats are acting, they’re worried about the damage the brothers can do.

David Koch attends a lunch in New York on Dec. 9, 2013, where former Bank of Canada governor Mark Carney, now Bank of England head, spoke. (Shannon Stapleton/Reuters) Koch Industries is one of the largest privately held companies in the U.S. It doesn’t release financial data publicly, but it’s thought to rake in annual revenues in the neighbourhood of $115 billion. The massive company, started by their father, Fred Koch, has its tentacles in the oil sector, consumer products, minerals, commodity trading, and much more.

If you’ve ever sipped out of a Dixie cup, mopped up a mess with a Brawny paper towel, worn workout attire with Lycra in it, or walked upon a Stainmaster carpet then you’ve experienced the vast reach of Koch Industries and the many companies it invests in or owns.

The brothers are majority stakeholders, which makes them very, very rich. The Bloomberg Billionaires Index puts their net worth at $100 billion and calls them the fifth and sixth richest people on planet Earth.

The Koch brothers don’t pocket all their profits. There are several charitable foundations associated with the family and they’ve given millions away to cancer research, the arts, and scholarships among other causes.

But it’s their funding of political candidates and campaigns that make them magnets for criticism and prompts the accusations that they are trying to buy America.

“They have single-handedly turned the American electoral process into a pay-to-play scheme,” Reid wrote on his website.

Republicans 'addicted to Koch'

“As for the Democrats here in the Senate, we will continue to defend American families from these oil baron bullies who want nothing more than to enrich themselves. We will continue to oppose their efforts to buy our democracy, because we represent America — not just rich Americans.”

On Reid’s website he writes about the Republicans being “addicted to Koch” (the surname is pronounced like the soft drink Coke, or, the drug) and it’s a line he’s repeated in the Senate while telling his opponents they should wear Koch Industries logos on their suits.

But it’s not just Reid, the anti-Koch campaign is a party-wide strategy. The Democratic Senatorial Campaign Committee started a website called kochaddiction.com that says the brothers are trying to buy the Senate and the Koch talking points are heard more often now by Congress members and Republican candidates.

The Democrats say they’re educating Americans about the Koch brothers, but likely they’re also trying to energize their base and use the Koch brothers as a fundraising tool while doing so. The Democrats are counting on their base not only for money but for votes this fall so they can keep control of the Senate.

Republicans have come to the Koch brothers' defence, asking what is so “un-American” about them employing thousands of Americans and making completely legal donations to political campaigns. They also point out that the Democrats have their own millionaire donors. Tom Steyer, for example, plans to spend millions of dollars this election cycle, primarily supporting Democrats and advocating for climate change policies.

The Koch Industries website also has a section meant to debunk what critics say about the duo and Charles Koch recently wrote an op-ed in the Wall Street Journal defending his business and saying he’s been the victim of character assassination.

According to Reid, his plan is working and he’s getting under their skin. But he’s not done yet.

"I haven’t been successful enough, because I’m going to continue,” he recently told reporters. “By the time we finish this, everyone is going to know who these, the two richest brothers in the world, are.”