Recently, I sat in a crowded committee room on Capitol Hill and asked the witness before me a simple question: "Congress has released a trove of political ads on Facebook bought by agents acting on behalf of foreign governments. Some of those ads were even paid for in Russian rubles, is that correct?"

The answer from Mark Zuckerberg, Facebook's CEO, was, "Congressman, that is correct."

While we deal in nuance frequently in public policy, on this there is no doubt: Our adversaries have found a way to interfere in our elections by discouraging, dividing, and disinforming the American electorate. A unanimous report from our nation's intelligence community, the findings of Independent Special Counsel Robert Mueller, a bipartisan Senate Intelligence panel, and now the testimony of the CEO of one of the world's most influential communication platforms have made that abundantly clear.

Here's how Mr. Mueller described the threat:

"Over the course of my career, I have seen a number of challenges to our democracy. The Russian government's effort to interfere in our election is among the most serious." He later added: "They're doing it as we sit here, and they expect to do it during the next campaign."

This existential threat to our democracy should alarm every American, and bring us together, not divide us. Foreign meddling in our affairs is exactly what our Founding Fathers feared most. In fact, in his farewell address, President George Washington warned, "Against the insidious wiles of foreign influence … a free people ought to be constantly awake, since history and experience prove that foreign influence is one of the most baneful foes of republican government."

Fortunately, our founders provided members of Congress the power to do something about it — and in the U.S. House, we have taken decisive action to safeguard our voting systems, modernize campaign finance law, protect the sanctity of our elections and defend our democracy.

I had the honor of voting on one of those measures immediately following my consequential conversation with Mark Zuckerberg, when the House passed H.R. 4617, the Stopping Harmful Interference in Elections for a Last Democracy (SHIELD) Act. The SHIELD Act is a comprehensive election security package that includes a bill I authored, the Firewall Act, which would stop the type of interference we saw on Facebook in 2016 by prohibiting foreign nationals from paying for online advertisements created to attack or support federal candidates.

This was not the first time this year that the House voted to strengthen election security and address the threat of foreign interference in our elections. Back in January, we also passed H.R. 1, the For the People Act, as our first order of business — one of the proudest moments yet as a member of Congress.

We have also passed the Honest Ads Act, the DISCLOSE Act, and the SAFE Act, each of which would enhance the integrity of our electoral and campaign finance systems. What do these important bills all have in common? They're collecting dust on Senate Majority Leader Mitch McConnell's desk in the Senate.

In the face of such dangerous interference by foreign adversaries — and with the knowledge that they're planning to do it again in 2020 — inaction is inexcusable. McConnell and his colleagues in the Senate have a choice: honor their sacred oath to the Constitution, or look away while Russia, China, North Korea, Iran, and yes, even Ukraine weaponize (actual) fake news to further deepen our divides and undermine our very sovereignty.

I have made the choice to honor my oath to the Constitution.

I invite and encourage McConnell and the majority in the Senate to join me.

Dean Phillips, a Democrat, represents Minnesota's Third District in the U.S. House.