When many of the people running a country believe (or claim to) that "global warming" is a hoax spread by liberals trying to establish a world government under Antichrist, you have to wonder at some point whether that country, however great its Constitution may be, has any hope of changing from within.
I have often mused that my best hope for helping "save the US" might be to back another horse, like Britain, that was in competition with us for global power and importance. (Germany would be better still, if I spoke German and could live there and contribute to the German economy). As that saner country grew stronger, and as the US grew weaker, the good guys (Germany, China, Japan, everyone else) could tell the bad guy (us) that they would economically embargo us into the stone age, unless we stopped pumping GHGs into the atmosphere -- unless we stopped making the planet unlivable for everyone.
Now I certainly don't think that I alone, by emigrating to Britain, could shift the balance of economic power in the world. However, if enough like-minded, moral people left the US, it might do some good.