At the same time, Facebook wants to avoid alienating the groups and candidates who depend on its platform for fund-raising and organizing. So in trying to find a way to please everyone on the issue, Facebook has managed to please no one.

The social network has now become an outlier in how freely it lets political candidates and elected officials advertise on its platform. While Mr. Zuckerberg declared last month that Facebook would not police political ads, Twitter said it would ban all such ads because of their negative impact on civic discourse. On Wednesday, Google said it would no longer allow political ads to be directed to specific audiences based on people’s public voter records or political affiliations.

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“As we’ve said, we are looking at different ways we might refine our approach to political ads,” a Facebook spokesman said in a statement.

The pressure on Facebook over what to do about political ad targeting has been unrelenting. Organizations on both sides of the political aisle — from as large as President Trump’s re-election campaign to smaller, grass-roots groups — have tried to persuade Facebook not to rein in the ad targeting.

“Making major changes to platform ad targeting would severely disadvantage Democrats and progressives who rely on Facebook for fund-raising and currently have a much smaller organic audience and current database of supporters to engage on and off the platform than Donald Trump,” said Tara McGowan, founder and chief executive of Acronym, a progressive nonprofit group.

Some Republican strategists said they also feared losing the ability to raise significant campaign donations online if Facebook reduced ad targeting.

On Friday, the Democratic National Committee, the Democratic Senatorial Campaign Committee and the Democratic Congressional Campaign Committee issued a joint statement condemning Google’s changes to its ad targeting policies.