Deciding who gets to say what online is a complex business in the best of times, and the 2020 election is showing social media platforms just how messy it can get.

The big picture: Balancing concerns over misinformation, hacking and foreign meddling against free-speech principles is already hard enough. Tackling it in real time in the middle of a political knife fight is almost certainly going to go awry.

What's happening: Fast action Wednesday by Facebook and Twitter to limit the reach of a questionably sourced New York Post story about Hunter Biden showed the world what aggressive misinformation policing on social media platforms looks like — and much of the world didn't like what it saw.

• On the right, pundits cried "censorship" while lawmakers demanded new in-person testimony from CEOs to defend their choices. 
• On the left, observers worried about the "Streisand effect" — the idea that trying to suppress or remove online information only draws attention to it.
• In newsrooms, the prospect of tech companies dialing back the distribution for newspaper stories gave journalists the creeps — even those with deep doubts about the quality of the New York Post article.

Driving the news: The two companies took different measures and relied on different rationales.

• Facebook decided to send the article to its third-party fact-checking partners for review. (The fact check is still in process.) While awaiting a report, the social network said it would limit the story's reach to reduce the likelihood of spreading misinformation.
• Twitter declared some of the information in the story, including photos and personal information, to be "hacked materials" and blocked sharing of links to the article.

Between the lines: In both cases, the companies were reacting to criticism of their performance during the 2016 election — and responding to what looked to them like a "hack and leak" operation similar to the pilfering of Democratic National Committee emails that year.

• While conservative activists and politicians and some journalists protested their actions, many security and disinformation experts praised their fast response.But the companies' messaging on their moves made a messy situation worse.
• Some of Facebook's fact-checking partners said they were surprised by the company's decision to reduce the Post story's reach even before a review. 
• At Twitter, CEO Jack Dorsey tweeted: "Our communication around our actions on the @nypost article was not great. And blocking URL sharing via tweet or DM with zero context as to why we're blocking: unacceptable."
• Late Thursday night, Twitter announced it was revising its "hacked materials" policy in response to the uproar over its ban on the New York Post story.

Our thought bubble: Facebook's "slow the spread" response looks more prudent than Twitter's "block the link" tactic, which infuriated users. But both moves looked haphazard. Three weeks before an election they have spent three years preparing for, the platforms still don't seem ready to take responsibility for their power.

These companies didn't set out to be the gatekeepers of political news. They'd rather write code, make money, and feel good about "connecting the world."

• But their success made them ubiquitous and they came to dominate the distribution of news and information. Now they can't duck making tough calls.

The bottom line: In that role, they know that they will never please everyone. But they're learning the hard way that they could do a better job of not ticking off everyone, too.

Go deeper:

Ted Cruz on Big Tech and the New York Post's Hunter Biden story

Facebook, Twitter clamp down on New York Post's Hunter Biden story