Who are the Koch brothers?

Charles and David Koch are each worth about $40.14 billion, the owners of Koch Industries, America’s second-largest private company. The billionaire brothers poured tens of millions into the 2012 presidential election in support of Republicans. And, though the 2014 midterm elections are months away, the two have already spent an estimated $30 million through their political advocacy group, Americans for Prosperity -- easily 10 times more money spent than any other big outside Democratic group -- to help achieve a Senate Republican majority in November.

However, despite the brothers being flush with money, power and influence, a majority of Americans (52 percent) still have not heard of them, according to the George Washington Battleground Poll released Tuesday. The research was carried out March 16-20 by the Tarrance Group and Lake Research, and surveyed 1,000 registered, likely voters.

Furthermore, among those who have heard of the GOP mega donors, the opinions aren’t too positive. About 25 percent of respondents say they have an unfavorable impression of the billionaire industrialists, while 12 percent find them favorable; 11 percent have no opinion of the siblings whatsoever.

The Koch brothers have been in the news recently after Democrats began demonizing their wealth and free-spending ways -- in a possible effort to recruit liberal donors, as the fight for the upper chamber heats up.

Senate Majority Leader Harry Reid, D-Nev., has called Charles and David Koch “shadowy billionaires” and described their tactics as “un-American.” He’s accused the two of pouring “unlimited money into our democracy to rig the system to benefit themselves and the wealthiest 1 percent.”

Representatives of Koch Industries differ. They say big spending on the part of the Democratic group Senate Majority PAC is another attempt to silence private citizens who don’t agree with the current administration’s policies.

“Rather than focusing on job creation and improving Americans’ lives for the betterment of this country, Reid has decided to focus instead on intimidating political opposition and squelching dissent,” Philip Ellender of Koch Industries told Politico.