A legislative proposal aimed at securing U.S. election systems from cyberattack is picking up additional support in the Senate as lawmakers grapple with how to respond to Russian election interference.

The bill, spearheaded by Sens. James Lankford (R-Okla.) and Amy Klobuchar (D-Minn.), is designed to help states upgrade their digital voting systems and boost information sharing between state and federal officials on potential cyber threats to U.S. elections.

The bill picked up new cosponsors in Sens. Mike Rounds and Bill Nelson (D-Fla.), the bipartisan leaders of the Senate Armed Services cyber subcommittee, on Tuesday.

Lankford is also hoping that Special Counsel Robert Mueller’s recent indictment of 12 Russian intelligence officers for launching cyberattacks in an effort to interfere with the 2016 election will add more urgency to passing the bill.

“It was further evidence in great detail that the Russian not only were trying to engage, but how they were engaged,” Lankford told The Hill in an interview Wednesday.

The bill is necessary to ensure confidence in future votes and securing state systems, he said, and future elections will be more at risk from hacking or interference if it is not passed.

“Anytime you have any spot where you have a weak link, that’s going to be your vulnerability in the future,” Lankford said.

The bill is making its way through the Senate at a time when President Trump has sparked a political firestorm after appearing to cast doubt on the U.S. intelligence community’s assessment of Russian election meddling during a joint press conference with Russian President Vladimir Putin on Monday.

The comments sparked bipartisan outrage, prompting Senate leaders to weigh new legislative actions, including additional sanctions, to punish Moscow. Trump walked back his comments on Tuesday, clarifying that he misspoke and accepts the intelligence community’s judgment on Russian interference.

The bill would authorize grants for states to replace outdated voting systems and institute requirements to improve information sharing between state and federal officials. It would also essentially codify into law actions that the Department of Homeland Security (DHS) is taking to share sensitive information with and provide security clearances to state elections officials.

Earlier this year, Congress allocated $380 million for states to immediately replace outdated voting systems with more secure ones.

Officials revealed last year that Russian hackers tried to probe election systems in 21 states as part of a broader interference plot in 2016. While officials maintain that the targeted systems were not involved in vote tallying and that no votes were changed, the revelations have spurred concerns about the vulnerability of American voting infrastructure to cyber sabotage.

Lankford and Klobuchar originally introduced the bipartisan legislation last December. When some states expressed concerns with various aspects of the bill, the senators began engaging with state officials to resolve the issues.

A revised version of the bill picked up support from leaders of the powerful Senate Intelligence Committee in March. But despite efforts to pass the bill – including by attaching it to must-pass defense policy legislation – it has not yet received a vote in the upper chamber.

But lawmakers have demonstrated increased interest in election security in recent weeks. The Senate Rules Committee has held two hearings on the issue. Lankford also said his staff is sitting down with counterparts on the Rules Committee to work out any issues with the bill before the committee ultimately votes on whether to advance it to the Senate floor.

It is unclear when, and if, the Rules Committee will vote on the legislation. Chairman Roy Blunt (R-Mo.) indicated Tuesday that the committee is working through details on the information reporting requirements by engaging with voting system vendors and state and local officials.

“We are trying to figure out for sure exactly what the best reporting regime would be,” Blunt told reporters. “I think, clearly, the [Department of] Homeland Security is trying to work with local officials in a way that is much more effective than they did in 2016. We are trying to determine what needs to be legislated and what needs to be a matter of oversight.”

Most of the hang-ups with the legislation have centered on state concerns with the bill. State officials have broadly been weary of federal efforts to address election security, fearing a federal takeover of elections that have historically been run by the states.

Lankford said that he met with state secretaries of state last week on the latest version of the bill and that the officials were “very supportive of where we are.” “They recognized how much input they have already given,” Lankford said Wednesday.

“I would assume it will continue to have tweaks all the way to the bitter end,” Lankford said. “I don’t expect large changes tough.”

The Mueller indictment, as well as President Trump’s recent comments about Russian interference in the election, could put momentum behind the bill.

On Friday, Mueller indicted 12 Russian intelligence officials for hacking emails of Democratic officials and waging cyberattacks against entities involved in administering elections – including hacking into a state elections board website and sending spear-phishing emails to state elections officials and an unnamed voting equipment vendor.

Meanwhile, Trump has continued to be besieged with criticism over his handling of the summit with Putin, stating Wednesday that no one had been tougher than he on Russia, although he also said Russia does not pose a threat to the United States.

Lankford said he was “very troubled” by the initial comments and that Trump’s subsequent statement on Tuesday clarified “a tremendous amount.” But, he said the bigger question going forward is what actions the Congress and the administration should take to push back on Moscow.

“Russia is not our friend,” Lankford said. “We’ve got to have a real push the Russians are not going to respond to words."