Sen. John McCain is backing legislation authored by two Democratic senators that would require sites like Facebook, Twitter, and Google to disclose who is paying for political ads. The bipartisan Honest Ads Act would essentially make sure political ads sold online are covered by the same rules as ads sold for TV, radio, and satellite.

The proposed legislation, which was authored by Democratic Senators Amy Klobuchar of Minnesota and Mark Warner of Virginia, still has a long and winding path before it could become a law.

But it’s notable because it’s the first—of what will likely be many—pieces of legislation crafted in response to disclosures by Facebook, Twitter, and Google that Russia exploited their platforms to spread propaganda and fake news in an effort to influence the 2016 U.S. presidential election.

“In the wake of Russia on the attack in the 2016 election, it is more important than ever to strengthen our defenses against foreign interference in our elections,” McCain wrote in a statement that was read by Klobuchar during a Thursday press conference. “Unfortunately, U.S. laws requiring transparency in political campaigns have not kept pace with the rapid advances in technology, allowing our adversaries to take advantage of these loopholes to influence millions of American voters with impunity.”

You can watch the entire press conference here:

[youtube https://www.youtube.com/watch?v=LVEJjNNLWlk]

Facebook’s general counsel will testify on Nov. 1 before a U.S. House of Representatives panel investigating possible Russian meddling in the 2016 U.S. election. Executives from Twitter and Alphabet’s Google also are expected to appear at a public hearing before the House intelligence committee.

Last month, Facebook CEO Mark Zuckerberg outlined the company’s plan to ensure election integrity in the future.