Dipayan Ghosh is a Shorenstein Fellow and co-director of the Digital Platforms & Democracy Project at the Harvard Kennedy School. He was a technology and economic policy advisor in the Obama White House, and later served as an advisor on privacy and public policy issues at Facebook. Follow him on Twitter @ghoshd7 .The opinions expressed in this commentary are those of the author; view more opinion at CNN.

(CNN) Tuesday's Democratic debate featured something we have never witnessed before on a presidential debate stage: 15 full minutes of open back-and-forth about how the government should contend with the increasing power of Silicon Valley .

At the center of the exchange was a tussle between Sen. Elizabeth Warren, who has been pushing for the break-up of tech giants like Facebook and Google, and Sen. Kamala Harris, who pointedly asked whether Warren would join her in demanding that Twitter suspend President Donald Trump's account on the platform.

This debate moment set the stage for what will doubtless be an election-long spat over what form regulations against internet companies should take.

This is a highly-charged and heavily politicized question, particularly for Democratic candidates. Last month, Facebook formalized a bold new policy that shocked many observers, announcing that the company would not seek to fact-check or censor politicians -- including in the context of paid political advertising, and even during an election season.

Over the past few days, this decree has pushed US political advertising into something like the Wild West: President Donald Trump, who will likely face the Democratic candidate in next year's general election, has already taken the opportunity to spread political lies with no accountability.

A frightening new world of political communication

In the aftermath of Facebook's announcement, Trump's presidential campaign disseminated an advertisement on Facebook's platform claiming that 2020 Democratic presidential contender Joe Biden had used his power as vice president to try to influence Ukraine to help his son, Hunter Biden.

The "facts" behind the Trump advertisement implicating Biden — which has been viewed on Facebook no fewer than five million times — have been definitively debunked , and CNN declined to air the ad for that reason.

This new Facebook policy opens a frightening new world for political communication — and for national politics. It is now the case that leading politicians can openly spread political lies without repercussion. Indeed, the Trump campaign was already spreading other falsehoods through online advertising immediately before Facebook made its announcement — and as one might predict, most of those advertisements have not been removed from the platform.

Should our politicians fail to reform regulations for internet platforms and digital advertising, our political future will be at risk. The 2016 election revealed the tremendous harm to the American democratic process that can result from coordinated misinformation campaigns ; 2020 will be far worse if we do nothing to contain the capacity for politicians to lie on social media.

The same capabilities by which political campaigns sliced up audience segments in 2016 via Facebook's advertisements will continue to exist in 2020. The difference will be that this time, the lies can be distributed by agents of the Trump campaign, instead of shell accounts operated by the Russian government and others.

Facebook's derogation of fact-checking will thus only lend greater credibility to coordinated disinformation operations — as in the case of the recent Trump campaign ad.

Warren responded to the Trump ad with a cheeky point: In an ad she has circulated over Facebook, she claims that "Mark Zuckerberg and Facebook just endorsed Donald Trump for re-election." Later in the ad, she acknowledges this is a falsehood, and contends that "what [Mark] Zuckerberg has done is given Donald Trump free rein to lie on his platform — and then to pay Facebook gobs of money to push out their lies to American voters."

Warren's mockery of the ad — and of the underlying policy that allowed its dissemination — helps illuminate how Facebook's new policy will have grave implications for our political future. Facebook's decision not to take down the Trump ad amounts to knowingly enabling the insidious political manipulation of American voters.

Facebook's power and "free expression"

The irony is that Facebook already censors advertisements -- including those placed by presidential campaigns in the United States -- for a host of reasons. One investigation found that the company had taken down paid content from four of the Democratic candidates, including 117 ads that had been placed by the Biden campaign, for reasons ranging from the use of profanity to the display of fake buttons.

It is disconcerting to think that by fiat, Facebook can deem a political ad to be dishonest because it contains fake buttons (which can deceive the viewer into clicking on a survey button when in fact there is no interactive feature in the ad), but the company will refuse to take action against ads containing widely-debunked political lies, even during an American presidential election.

This perilous inconsistency in Facebook's policy decisions is a sign that its corporate power has grown too great. Concern for the public interest and the health of our democracy should compel us to action. And the only entity that has the power to do anything to improve the situation for the American people is Congress.

Facebook has one principal counterargument against regulation: that the company must maintain strong commitments to free speech and freedom of political expression. This came across in Mark Zuckerberg's speech at Georgetown University on Thursday, in which he described social media as a kind of "Fifth Estate" and characterized politicians' calls to take action as an attempt to restrict freedom of expression. Quoting at times from Frederick Douglass and Supreme Court jurisprudence, Zuckerberg said "we are at a crossroads" and asserted: "When it's not absolutely clear what to do, we should err on the side of free expression."

Unfortunately for Facebook, this argument holds little water. If you determine that an ad containing a fake button is non-compliant because it "[entices] users to select an answer," then you certainly should not knowingly broadcast ads that entice voters to unwittingly consume publicly-known lies -- whether they are distributed by the President or any other politician. Indeed, as one official in Biden's presidential campaign has noted , Zuckerberg's argumentation amounts to an insidious "choice to cloak Facebook's policy in a feigned concern for free expression" to "use the Constitution as a shield for his company's bottom line."

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Behind what the company claims to be a commitment to free speech lies a commercial convenience.

Regulatory policy is the way forward

If Facebook cannot take appropriate action and remove paid political lies from its platform, the only answer must be earnest regulation of the company -- regulation that forces Facebook to be transparent about the nature of political ads and prevents it from propagating political falsehoods, even if they are enthusiastically distributed by President Trump.

Our nation has always aspired to place the interests of our democratic purpose over the interests of markets. Silicon Valley should be no exception.