Katrina vanden Heuvel, The Washington Post

Despite the tantalizing prospect of a wave election in November, Democrats face major structural obstacles to winning majorities in Congress. Recently, the potential impact of partisan gerrymandering has received needed attention, but one issue that is flying largely under the radar is the sheer amount of special-interest money that progressive candidates will have working against them.

2018 is expected to be the most expensive midterm cycle in history, beyond the $3.8 billion spent on races in 2014. That number is staggering, but not surprising, given the proliferation of money in politics over the past decade. While both parties have contributed to the current state of affairs, the exorbitant cost of mounting a credible campaign today clearly disadvantages insurgent progressive candidates and their supporters while bolstering the power of candidates with the most appeal to the donor class. In general, that’s good news for Republicans.

This dynamic is plainly visible in the spending so far during the 2018 cycle. As of this writing, political action committees have doled out nearly a quarter of a billion dollars to congressional candidates this cycle. Thirteen of the top 15 recipients of contributions from PACs are Republicans, according to the Center for Responsive Politics. Among them are party leaders including House Speaker Paul D. Ryan (Wis.) and House Majority Leader Kevin McCarthy (Calif.) as well as vulnerable members from blue states, such as Rep. Peter J. Roskam (Ill.) and Rep. Erik Paulsen (Minn.), whose races could help swing the balance of power in Washington.

Spending by outside groups has also exploded. To date, these groups have spent nearly $90 million this cycle, almost double the amount spent at this point four years ago. More than two-thirds of that money has come from Republican-leaning organizations, which rely heavily on funding from conservative mega-donors including the Koch brothers, Sheldon Adelson and the Mercer family. Much has come from “dark money” organizations that aren’t required to disclose their donors. One such group is the National Rifle Association’s Institute for Legislative Action, the nonprofit arm of the right-wing gun lobby, whose $35.2 million spent in the 2016 election was the most of any dark-money organization.

While this deluge of spending poses a serious challenge, some Democrats have found a way to use it to their advantage by actively campaigning against it. In Pennsylvania, for example, Democrat Conor Lamb, the unlikely winner last month of a special election in a congressional district that President Trump carried by nearly 20 points, turned the money spent against him into a central part of his pitch. He bolstered his argument that the Republican tax-cut bill was “written for corporate donors” by refusing to accept money from corporate PACs. And he railed against dark money, which he told voters was being used “to drown out the truth and drown out your voice.”

There are similar stories of other candidates who are not just talking about the corrosive influence of money in politics, but actually walking the walk. In all, more than 100 federal candidates have committed to rejecting donations from corporate PACs. Hundreds are also refusing to accept NRA money in the wake of the school shooting in Parkland, Fla. Like Sen. Bernie Sanders (I-Vt.) did in 2016, Lamb, Rep. Beto O’Rourke (D-Tex.) — who is refusing all PAC contributions for his Senate run — and others are proving that Democrats don’t need to cater to big donors to compete. The rest of the party would be smart to follow their lead.

Encouragingly, the trend has even reached potential 2020 presidential candidates, as Sens. Kirsten Gillibrand (D-N.Y.) and Cory Booker (D-N.J.) have both sworn off corporate PAC money. “We won’t be able to bring down Medicare drug prices, stop companies from outsourcing our jobs or start to rebuild the middle class until we can stem the unlimited influence special interest money applies over politicians,” Gillibrand explained. Rather than selling out to match Republicans dollar for dollar, Democrats can increase their appeal to grass-roots voters by taking a firm stand against corporate influence. And by championing reform legislation such as the Government By the People Act, a plan introduced by Rep. John Sarbanes (D-Md.) that would implement a system of matching public funds in federal elections, Democrats can demonstrate that they are committed lifting up the voices of regular voters.

Reform groups such as Every Voice have long argued that the effort to get big money out of politics must also bring people back in, which is what Sarbanes’s bill and many state and local reform laws do. The cost of elections today increases the power of the privileged few while diminishing that of working Americans and, as such, harms democracy itself. Real reform must turn this on its head. As Supreme Court Justice Stephen G. Breyer warned in 2014, “Where enough money calls the tune, the general public will not be heard” — unless that money comes from the public itself.