The Washington Post’s Ezra Klein recently lamented that America has “a deeply unbalanced political system.” He highlighted a chart showing that business owners and employees donate billions to politicians, while unions give only a few tens of millions. True enough, but this does not make labor “totally outgunned,” as he claims. Unions give little directly to politicians because they run their own political machines.

Businessmen who support politicians give them money, and the candidates use that money to run their campaigns. Unions instead prefer to run their own campaigns. This gives them a machine they can turn against politicians who do not toe the line. Unions conduct polling, develop and run TV ads, and conduct massive get-out-the-vote operations themselves. Such activities made unions the top outside spenders in the 2010 election cycle.

But because unions never relinquish their money to a candidate, none of this gets reported to the FEC, so it can look like they have little clout. Fortunately, the Department of Labor requires private-sector unions to file detailed financial-disclosure reports to their members. These reports show unions spend far more on politics than they report to the FEC. Over the past four election cycles, unions spent more than $4 billion on political activities and lobbying. In the 2012 election cycle alone, they spent $1.4 billion.

Moreover, these reports understate total union spending. A majority of union members work in government, but federal transparency regulations only cover unions with at least one private-sector or federal employee as a member. Consequently most government union locals do not have to file.

Unions spend billions on politics. The fact that they give little directly does not make their influence any less real. Take their campaign to get rid of secret ballots in organizing elections: Despite its being an overwhelmingly unpopular cause, a majority of the House of Representatives acted at the behest of union lobbyists and voted to do just that. Businesses certainly don’t appear to think unions lack clout. Jay Clemens, president of Associated Oregon Industries, told a union official after the 2012 election: “You guys don’t lose anything.”

Unions do not, as Klein put it, lack the “money to be a particularly powerful force in American politics.” They simply report it differently than everyone else.