Oh, I'm sure he has some influence in things, but isn't this about as useful as someone paying the NFL to make Bud Light the official beer of football? When the other side of the deal wants yuan, yen or euros, you're not going to spend much time thinking about what the President of Mexico says.
I also don't think he's committed to the US dollar at all, but accepts the fact that a lot of Mexico's economy depends on US manufacturing cash and USD remittances.
This is such a big deal. People don't realize that AMLO is basically Mexican Bernie Sanders, but tougher and farther left. He's not some blind supporter of American Hegemony.
Bernie is far left in the USA, and AMLO is far left in Mexico. We aren't discussing Europe, so your spectrum isn't relevant.
AMLO is a nationalist, you are right there - and in a nation that is hostile-to-ambivalent about the USA it's really telling for him to say this. Maybe people are waking up to how shitty a China led world would be.