They have their NPOV[1] policy, and seem impressively unbiased to me, given the various divisive situations they have to try to cover.
[1] https://en.m.wikipedia.org/wiki/Wikipedia:Neutral_point_of_v...
As a non American this is very obvious to me.
Even Reuters that was supposedly meant to be a non-biased media outlet is clearly left-leaning at this point
I had a look at the most potentially controversial topics I could find right now, and I say they seem fair. For example: https://www.reuters.com/world/us/dozens-detained-us-immigrat... (on ICE arrests in NY) and https://www.reuters.com/world/middle-east/what-would-wider-r... (on recognition of a Palestinian state).
Indeed, Wikipedia lists it as a good source[1]. It's worth comparing that to outlets like CNN (reliable, but "... talk show content should be treated as opinion pieces. Some editors consider CNN biased, though not to the extent that it affects reliability.") or The Wall Street Journal ("Most editors consider The Wall Street Journal generally reliable for news. Use WP:NEWSBLOG to evaluate the newspaper's blogs, including Washington Wire. Use WP:RSOPINION for opinion pieces.")
[1] https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources/Per... ("Reuters is a news agency. There is consensus that Reuters is generally reliable.")
When evaluating a news source for whether it’s unbiased, left or right, we necessarily look at the stories it presents and check whether they align with and present in a positive light a particular political option.
We call it „unbiased” if it doesn’t particularly favor any of these.
We’re already in the realm of US electoral politics - for a second we can assume that nothing else exists.
In 2016 the political landscape shifted drammatically and presenting the „right wing” option in a favorable light required certain concessions when it comes to previous journalistic standards.
So, just by sticking to its previous guidelines, the AP would automatically shift to the „left” - because the landscape changes.
It would be more accurate to say that the world shifted underneath AP’s lense and so it immediately started being perceived as left wing.
https://app.adfontesmedia.com/chart/interactive?utm_source=a...
(I expect a lot fewer people to reference that chart in the future unless they fix the new user interface)
These measurements do feel a bit arbitrary, since our definitions of left and right bias are subject to change. For example, one interesting thing about the AP is that their stylebook used to urge their reporters to avoid even using the word "Palestine," one of many ways they put their thumb on the scale in favor of Israel in that conflict. (not sure what it says today) They somewhat famously fired a reporter for having participated in some college activism related to the Arab-Israeli conflict that would seem very quaint and anodyne today, a firing that stirred up journalists and was pretty widely regarded outside the right wing media sphere as unfair. (ironically, a week or two later the IDF destroyed the AP's Gaza office in an airstrike)