Facebook could also defend political ads by conceding that it must continue the practice to maintain its status and markets. Besides Mr. Trump, who spent $70 million on Facebook ads in 2016 (far more than his main rival, Hillary Clinton), the pro-Brexit Conservative Party in Britain, Prime Minister Narendra Modi’s party in India, President Jair Bolsonaro’s party in Brazil and President Rodrigo Duterte’s party in the Philippines all relied on Facebook and Facebook-owned WhatsApp to achieve and maintain power. All of those countries are major Facebook markets, and they all could threaten Facebook with regulatory backlash if the company disappointed their leaders.

Over all, Facebook has no incentive to stop carrying political ads. Its revenue keeps growing despite a flurry of scandals and mistakes. So its leaders would lose little by being straight with the public about its limitations and motives. But they won’t. They will continue to defend their practices in disingenuous ways until we force them to change their ways.

We should know better than to demand of Facebook’s leaders that they do what is not in the best interests of the company. Instead, citizens around the world should demand effective legislation that can curb Facebook’s power.

The key is to limit data collection and the use of personal data to ferry ads and other content to discrete segments of Facebook users — the very core of the Facebook business model.

This task would be easier in some countries than others. The First Amendment of the United States Constitution severely limits policy options in America. But here’s something Congress could do: restrict the targeting of political ads in any medium to the level of the electoral district of the race. Tailoring messages for African-American voters, men or gun enthusiasts would still be legal, as this rule would not govern content. But people not in those groups would see those tailored messages as well and could learn more about their candidates. This law would apply not just to Facebook, Twitter and YouTube, but also to all targeted ads delivered via cable boxes or devices.

Currently, two people in the same household can receive different ads from the same candidate running for state senate. That means a candidate can lie to one or both voters and they might never know about the other’s ads. This data-driven obscurity limits accountability and full deliberation.

If the same political ads were to reach everyone in a state, district or even country, they would not just appeal to marginal constituencies, might not tend toward extremism, and could not get away with lies quite so easily. Journalists, citizens and political opponents would see the same ads and could respond to them. A reason to be concerned about false claims in ads is that Facebook affords us so little opportunity to respond to ads not aimed at us personally. This proposal would limit that problem.