This story was originally published by Mother Jones and is reproduced here as part of the Climate Desk collaboration.

The Paris climate agreement faces its first international stress test since President Donald Trump announced in the Rose Garden he will pull the U.S. out from the landmark 2015 deal to curb greenhouse gas emissions.

In May, when world leaders met for the G7, they were trying to convince and cajole Trump to understand the existential importance of addressing climate change. With his decision to withdraw, Trump has marginalized the U.S. in the G20 meeting this week in Hamburg, Germany. His administration’s “America First” agenda has been disruptive when it comes to the future of climate action; this meeting may signal if other nations will follow, or not follow, his lead.