On the eve of former special counsel Robert Mueller’s much anticipated testimony in the House of Representatives, Senate Democrats are trying to refocus the nation’s atten­tion on Russian interference in US elections. Interference that they predict, and the intelligence community agrees, will only increase in 2020.

"The Russians are absolutely intent on trying to interfere with our elections through foreign influence,” FBI director Christopher Wray testified before the Senate Judiciary Committee on Tuesday.

There are a number of bipartisan efforts to protect the nation’s electoral process: The Honest Ads Act, cosponsored by Amy Klobuchar (D-Minnesota) and Lindsey Graham (R-South Carolina), is aimed at keeping foreign actors from buying social media ads, among other things. The Duty to Report Act would “impose a legal duty on federal campaigns, candidates, and PACs to report offers of assistance from foreign nationals.” But one high hurdle to enacting those policies remains: Republican leadership.

“The only people that are stopping these kinds of common-sense measures from becoming law of the land are … [Senate majority leader] McConnell and President Trump,” said Senator Mark Warner (D-Virginia), who serves as vice chair of the Senate Intelligence Committee, at a press conference at the Capitol on Tuesday.

Warner and other Democrats argue that the holes in the nation’s electoral system are so obvious that proponents already have the votes to pass a myriad of bipartisan bills.

“We’re talking about low-hanging fruit that, if it came to the floor of the Senate, they would pass with close to 80-plus votes,” Warner said, claiming that these measures could easily bypass a presidential veto.

Still, Republican leaders dismiss these efforts as unneces­sary, and they point to the last federal election as their case in point. “Most of our members, at least, believe that with the additional resources given to the states and the way the states improved their game in 2018 that we’re on the right track,” Senate majority whip John Thune told WIRED.

Congress set aside $380 million last year for states to beef up election security through the Help America Vote Act, but experts say more federal funding is needed. The nonpartisan Brennan Center for Justice released a report just last week arguing that “even after these funds have been spent, many election security needs will remain unmet at the state and local level.”

Thune, speaking on behalf of McConnell and other leaders, said the GOP leadership’s reticence stems from fears that Democrats are trying to de-federalize local elections.

“They want to nationalize our election process, and I think most Republicans think a decentralized process is less likely to be gamed than if we had a nationalized system that does it,” Thune said. “The states by and large—with few exceptions—they do a really good job. They’ve invested, I think, heavily in firewalls and they worked effectively in 2018, and we hope that will be true in 2020.”

No Democrat currently in office is arguing to nationalize elections. Senate Democrats are, however, calling for more resources from Washington, along with more stringent rules governing federal elections. Their legislative proposals include the Protecting American Votes and Elections Act, which no Republican has yet sponsored. Among other things, the bill would require states to use voting machines with paper ballots, rather than digital-only systems; paper ballots serve as a backup and can be audited in the event of suspected interference or cyberattack.

“There’s no reason we shouldn’t be able to advance that bill,” said Senator Klobuchar. “That’s really disturbing that we’re not getting that done.”

These senators, along with the bipartisan partners who have signed on to many of their proposals, fear the country hasn’t learned the right lessons from 2016. But they differ on what exactly the biggest threats are.