And I'm generally in agreement that most attempts to quantify 'truth' in media are hopelessly dependent on personal bias---but this mostly shows up in category #2 in my list. In things where you'd never know the difference if it were true or not, because it would never affect you either way.

The reason I thought a news service like this would work better as a government service than a private entity is because a government news service's commitment to the principles I listed could be defined by enforceable laws. "Likely to materially affect people" is something that you could reasonably argue about in a courtroom, just as much as other fuzzily-defined legal concepts like libel or false advertising.

I'm imagining a news agency whose legal responsibilities were defined in such a way that it could be sued if one of the following happened:

1. It reports something that no reasonable person would believe meets the criteria.

2. Readers experience some kind of material harm that could have been avoided if they had read news reported in another outlet but not this one. And this harm is not the result of the reader being in some very small minority of readers (say, <1%), because after a certain point this will always be true for things that affect a very small number of people.