One of the issues being hotly debated among presidential candidates and political operatives leading up to the 2020 campaign isn't health care, or the economy — it's free speech.

Why it matters: Disagreements about how to apply the First Amendment to the speed and scale of social media are consuming the political debate this election cycle and cementing unprecedented levels of polarization.

Driving the news: In the Trump era, Republicans have found a way to leverage the loose freedoms of social media to gain an upper hand in some elections. Now, Democrats are demanding that big tech companies do something about it.

Speaking at an event in New York City Monday, Hillary Clinton said Facebook CEO Mark Zuckerberg “should pay a price” for what he is doing to democracy.

Her comments come as more Democrats argue that Facebook shouldn't let President Trump, or any political candidate, get away with spreading falsehoods via political ads.

Almost every major Democratic presidential candidate has condemned Facebook for its political advertising policy, while conservatives for the most part have endorsed it, or stayed quiet.

Conservatives are instead focusing their political attacks on censorship, arguing that Democrats and liberal firms are out to censor their speech to voters.

Last week, Trump campaign manager Brad Parscale ridiculed Twitter's recent decision to ban political ads as "yet another attempt by the left to silence Trump and conservatives." It's an argument he's been using against companies for months.

Trump's campaign and key allies plan to make bias allegations by social platforms a core part of their 2020 strategy, officials told Axios in September.

Case in point: Donald Trump Jr.'s new book —"Triggered: How the Left Thrives on Hate and Wants to Silence Us" — is out today.

The issue of hate speech has become another political flashpoint, with Democrats and Republicans sparring over whether their political perspectives are fair game online.

Minority advocacy groups have pushed Facebook to ban Trump's ads around immigration that use nativist undertones and false ads that allege two Muslim members of Congress are "‘anti-Israel, anti-AMERICAN, and pro-terrorist."

Meanwhile, Democrats on the campaign trail are calling for Section 230 of the Communications Decency Act, an internet provision that protects tech companies from liability for the content people post on their platform, to be reexamined.

The big picture: A majority of Americans (73%) say voters in both parties “cannot agree on the basic facts," according to Pew Research Center.

Disagreement over basic facts is making it easier for politicians to spew falsehoods without paying a price.

And while news organizations scramble to fact-check these statements, it's proving difficult to do in real time. Trust in mass media is also at a near all-time low.

Yes, but: Despite the onslaught of attention candidates and pundits are bringing to this issue, free speech and the First Amendment rarely come up as highly important issues to voters amongst polls.

The bottom line: The free speech debate is creating a hyper-polarized environment that candidates are exploiting ahead of the 2020 presidential election.

It's also an entry point for politicians to talk about regulating Big Tech. Unlike with machine learning bias or anti-competitive behavior, the harm from lying in political ads is easy for voters to understand and legislators to act against.

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