Public officials choose to live a live under intense scrutiny and should expect to be challenged on their positions and able to provide well-reasoned arguments for their opinions and actions. "Fact checking" is a necessary component of a functional democracy. As small and local news outlets die en masse from the social media takeover, someone needs to pick up the slack.

>Once you start fact checking where does it end?

With all the facts being checked?

I imagine he's suggesting that it will end with all the opinions being checked.

Nothing wrong with that, particularly if those opinions are communicated in a way that makes them look like statements of fact.

Someone being able to say "I think your opinion is wrong" is no less a freedom of speech matter than someone being able to state an opinion in the first place. Freedom of speech does not, or at least it should not, give special privilege or protection to the first person who speaks.

This is a tough position for Twitter because they now have to fact check practically all of his tweets. Any tweet not checked will be seen either as tacit endorsement by Trump's political opponents or 'undeniable truth' by some portion of their users regardless of validity.

The line between fact and opinion can become very blurry. Whatever you do there will be a lot of issues that can’t be fact checked.