This year, millions of Americans have voted in congressional primaries and runoffs . These voters, who comprised just 15 percent of the eligible electorate in the last midterm election season, are wasting their time.

Thus far, only four incumbents running for re-election this year have lost their primaries, and 121 of those incumbents ran unchallenged.

One might assume that incumbents are nearly invincible because they pay attention to their constituents. Even though 8 in 10 Americans are "dissatisfied" with Congress, we mostly love our own representatives. Or so the thinking goes.

But this narrative breaks down under scrutiny. In April, a Gallup poll found that only half of voters believed their representative deserved to be re-elected.

With such middling approval ratings, we'd expect dozens of incumbents to lose their seats each election cycle. Yet they don't – mostly thanks to generous support from super PACs, which spend millions of dollars to prop up incumbents and smear challengers. Incumbents return the favor by voting for legislation that benefits these mega-donors.

Super PACs, formally known as "independent expenditure-only committees," became an electoral juggernaut after the Supreme Court's 2010 Citizens United decision.

The Supreme Court ruled that corporations, political parties and individuals can donate unlimited funds to super PACs so long as those PACs remain "independent" – in other words, they can't coordinate directly with candidates or directly donate money. They can, however, spend tens of millions of dollars on advertisements and get-out-the-vote efforts.

The ruling has been a godsend for incumbents. During the most recent midterm election cycle, super PACs spent nearly twice as much money promoting incumbent House members as they did promoting challengers. This cycle, more than 92 percent of all PAC spending has gone to incumbents.

Unsurprisingly, most PAC money comes from corporations and ultra-wealthy donors. During the 2016 primary season, nearly half of the $600 million in super PAC donations came from fewer than 50 individual donors. So far this cycle, just 10 wealthy donors have given over $76 million to super PACS. That figure will skyrocket as the November elections draw closer.

Politicians are desperate to keep this money flowing. They no longer care what their constituents believe – they're completely beholden to their donors. In fact, the bottom 90 percent of American income earners have barely any influence over government decisions, according to a joint Northwestern-Princeton University study of about 2,000 public opinion surveys.

Many Americans support campaign finance reform to get big money out of politics. But with super PACs protected by the Citizens United ruling and Congress in no mood to turn off the cash spigot, the chances for meaningful reform look slim.

Party committees aren't helping either. Both sides discourage challengers from within, under the premise that competition disrupts party unity and wastes resources.

Handwringing and complaining about money in politics isn’t the answer. It's time for voters to fight fire with fire.

Small-dollar donors can't move the needle on their own. No politician will notice an individual contribution of $20, $50, or even $200. But in aggregate, these small-dollar donors are immensely influential.

Consider the 2016 presidential election. Sen. Bernie Sanders' campaign and various fundraising committees raised nearly $230 million and almost took down a heavily-favored Hillary Clinton for the Democratic presidential nomination. More than half of those funds came from donations under $200. The average donation? Less than $30.

Or look at Donald Trump's campaign, which raised more than $86 million from small-dollar donors. Those donations accounted for two-thirds of his total fundraising – a higher percentage than President Obama enjoyed in 2008 and 2012.

By banding together financially, small-dollar donors can sway federal elections. And they can do so via the preferred vehicle of big-dollar donors – super PACs.

Super PACs sound nefarious. But they're just legal entities for raising and spending political contributions. Anyone can set up a super PAC. If fed-up voters unite behind a handful of such organizations, they could defeat lazy, corrupt and out-of-touch incumbents in both parties.

The average incumbent member of the House has raised just over $1 million this election cycle. If just 5,000 constituents contributed $200 to a super PAC opposed to that incumbent's candidacy, they could neutralize that fundraising advantage.

Right now, super PACs are a tool for the wealthy and well-connected. They needn't be. With a modicum of organization, everyday voters could transform super PACs into the swamp's worst nightmare.

Editor's Note: A version of this article originally published on Fox News, and has been published on IVN with permission from the author.