Yes, by journalists in the press, and perhaps by their opponents. But just because you sell billboard space, or ad space, doesn't mean you should be responsible for that fact checking.

There's a reason newspapers would separate out advertising and editorial content and identify them as such.

The counter argument typically is "but what if no one sees the countervailing message?!?" Shouldn't such a verdict be affixed to the message as a visual mark of sin or righteousness?

Counter ideas with ideas, not imprimaturs.

That said, I'd love to have a "No Tweet" litmus test for Presidential candidates. "I promise, when I'm President, that I will never personally tweet from my own account."

By whom? Every side can argue either way to truth or lie.

Looking at the arguments in the multiple posts of this topic / concept we have people saying President Trump’s statement is false and true. It depends on the perspective, a significant amount of which is tribal based. You can get a great example of how a person’s thoughts change depending on who says it if you watch any of the YouTube videos of people asking opinions on a quote; when it was revealed to be someone from their tribe, BOOM!, perspective change.

Fact checking could be accomplished by a three person team that has items presented to them without context. But, we would need them to be isolated from society to ensure their purity in a subject matter.