Twitter recently made the decision to outright ban political ads.
"This isn't about free expression," Twitter CEO Jack Dorsey said on Twitter, where he announced the ad policy change. "This is about paying for reach. And paying to increase the reach of political speech has significant ramifications that today's democratic infrastructure may not be prepared to handle. It's worth stepping back in order to address."
Some politicians praised the move, including former Vice President Joe Biden and former Secretary of State Hillary Clinton — but President Trump's campaign manager, Brad Parscale, asserted that the move was, "yet another attempt to silence conservatives."
If Facebook were to ban political ads, it would run into another issue — one that Twitter is almost certain to face: deciding what is and isn't "political" speech.
Zuckerberg highlighted as much during his speech at Georgetown.
"Even if we wanted to ban political ads, it's not clear where we'd draw the line," he said. "There are many more ads about issues than there are directly about elections. Would we ban all ads about healthcare or immigration or women's empowerment? If we banned candidates' ads but not these, would that really make sense to give everyone else a voice in political debates except the candidates themselves?"
It's a reasonable point — if Facebook were to ban "political" ads, it would have to spend a lot of time defining what is and isn't political speech. And then it would come under fire for policing free speech.
"There are issues any way you cut this," Zuckerberg said, "and when it's not absolutely clear what to do, I believe we should err on the side of greater expression."