There has been a lot of talk about how the USA pulling out of the Paris Climate Accord is stupid in various forms. Stupid enough that many US cities and states are trying to meet their climate accord obligations independently.
But one thing doesn’t appear to have been mentioned: That the USA made a firm commitment to follow the Paris accords, and then broke that agreement. Which makes the US government oath-breakers – an untrustworthy party when it comes to international agreements.
You can make all sorts of excuses for repudiating the Paris Accord – perhaps it wasn’t in the best interests of the US to take part, or that it was unfair to the US in some way.
But fundamentally, the USA made an agreement and then repudiated it. It is now less trustworthy than it was before.