SAN FRANCISCO >> Defying pressure from Congress, Facebook today said that it would continue to allow campaigns to use the site to target advertisements to particular slices of the electorate and that it would not police the truthfulness of the messages that they send out.

The stance put Facebook, which is the most important digital platform for political ads, at odds with some of the other large tech companies, which have begun to put new limits on political ads.

Facebook’s decision, which company executives had telegraphed in recent months, is likely to harden criticism of the company heading into this year’s presidential election.

Political advertising cuts to the heart of Facebook’s outsize role in society, and the company has found itself squeezed between liberal critics who want it to do a better job of policing its various social media platforms and conservatives who say their views are being unfairly muzzled.

The issue has raised important questions regarding how heavy a hand technology companies like Facebook — which also owns Instagram and messaging app WhatsApp — and Google should exert when deciding what types of political content they will and will not permit.

By maintaining a status quo, Facebook executives are essentially saying they are doing the best they can without government guidance and see little benefit to the company or the public in changing.

In a blog post, a company official echoed Facebook’s earlier calls for lawmakers to set firm rules.

“In the absence of regulation, Facebook and other companies are left to design their own policies,” Rob Leathern, Facebook’s director of product management overseeing the advertising integrity division, said in the post. “We have based ours on the principle that people should be able to hear from those who wish to lead them, warts and all, and that what they say should be scrutinized and debated in public.”

Other social media companies have decided otherwise, and some had hoped Facebook would quietly follow their lead. In late October, Twitter’s chief executive, Jack Dorsey, banned all political advertising from his network, citing the challenges that novel digital systems present to civic discourse. Google quickly followed suit with limits on political ads across some of its properties, though narrower in scope.

The new policy drew broad criticism. Lawmakers and regulators focused on the targeting of ads to particular slices of the electorate, often called microtargeting, as a top concern. Some critics said the ability to aim ads in such a way made it easier to spread divisive or misleading information.

Ellen Weintraub, who sits on the Federal Election Commission, said in a Twitter post this morning that Facebook’s plan was “weak” and the company was “hurting democracy.” She has called for the elimination of microtargeting for political ads.

“No one is a bigger believer in transparency than I,” she wrote. “But here, proposing ‘transparency’ solutions is window-dressing when Facebook needs to be putting out the housefire it has lit.”

Sen. Brian Schatz, D-Hawaii, said politicians should be held to the same standards as every other Facebook user.

“Politicians should not be free to lie and use Facebook’s targeting system to launch these lies onto the internet with great velocity,” Schatz said in a statement. “I worry that this is another example of Facebook underestimating the damage they are doing to the very fabric of our democracy.”

Facebook has played down the business opportunity in political ads, saying the vast majority of its revenue came from commercial, not political, ads. But lawmakers have noted that Facebook ads could be a focal point of President Donald Trump’s campaign as well as those of top Democrats.

“This is about money,” Rep. David Cicilline, D-R.I., wrote on Twitter. “Specifically, the $6 billion that will be spent on political ads in 2020 that Facebook will use to continue increasing their profits at the expense of our democracy.”

Facebook’s hands-off ad policy has already allowed for misleading advertisements. In October, a Facebook ad from the Trump campaign made false accusations about former Vice President Joe Biden and his son Hunter Biden. The ad quickly went viral and was viewed by millions. After the Biden campaign asked Facebook to take down the ad, the company refused.

“Our approach is grounded in Facebook’s fundamental belief in free expression, respect for the democratic process and the belief that, in mature democracies with a free press, political speech is already arguably the most scrutinized speech there is,” Facebook’s head of global elections policy, Katie Harbath, wrote in the letter to the Biden campaign.

In an attempt to provoke Facebook, Sen. Elizabeth Warren’s presidential campaign ran an ad falsely claiming that the company’s chief executive, Mark Zuckerberg, was backing the reelection of Trump. Facebook did not take the ad down.

Criticism seemed to stiffen Zuckerberg’s resolve. Company officials said he and Sheryl Sandberg, Facebook’s president, had ultimately made the decision to stand firm.

In a strongly worded speech at Georgetown University in October, Zuckerberg said he believed in the power of unfettered speech, including in paid advertising, and did not want to be in the position to police what politicians could and could not say to constituents. Facebook’s users, he said, should be allowed to make those decisions for themselves.

“People having the power to express themselves at scale is a new kind of force in the world — a Fifth Estate alongside the other power structures of society,” he said.

Facebook officials have repeatedly said significant changes to its rules for political or issue ads could harm the ability of smaller, less well-funded organizations to raise money and organize across the network.

Instead of overhauling its policies, Facebook has made small tweaks. Leathern said Facebook would add greater transparency features to its library of political advertising in the coming months, a resource for journalists and outside researchers to scrutinize the types of ads run by the campaigns.

Facebook also will add a feature that allows users to see fewer campaign and political issue ads in their news feeds, something the company has said many users have requested.

There was considerable debate inside Facebook about whether it should change. Late last year, hundreds of employees supported an internal memo that called on Zuckerberg to limit the abilities of Facebook’s political advertising products.

On Dec. 30, Andrew Bosworth, head of Facebook’s virtual and augmented reality division, wrote on his internal Facebook page that, as a liberal, he found himself wanting to use the social network’s powerful platform against Trump.

But Bosworth said that even though keeping the current policies in place “very well may lead to” Trump’s reelection, it was the right decision. Dozens of Facebook employees pushed back on Bosworth’s conclusions, arguing in the comments section below his post that politicians should be held to the same standard that applies to other Facebook users.

For now, Facebook appears willing to risk disinformation in support of unfettered speech.

“Ultimately, we don’t think decisions about political ads should be made by private companies,” Leathern said. “Frankly, we believe the sooner Facebook and other companies are subject to democratically accountable rules on this the better.”