"But for each of those explanations, there is a counter-explanation. Consider the rationale for Trump’s response to Trudeau’s news conference. Macron’s office issued a statement that said “international cooperation can not be dictated by fits of anger and throwaway remarks.” In other words, this wasn’t merely a difference of opinion over policy. It was personal. When you factor in Trump’s preference to go it alone, the issue becomes even more complicated. U.S. allies, as I have written, have little choice but to go along with Trump’s seemingly erratic behavior. They have no other allies. Trump has made his own preferences clear, praising China’s Xi Jinping and Russia’s Vladimir Putin while bizarrely seeking Russia’s inclusion in the G7, a grouping from which it was suspended following its invasion in 2014 of Ukraine’s Crimea.
At this point, given Trump’s proclivity to withdraw from every single Western-engineered global agreement, from the Paris climate change pact to the Iran nuclear deal and the Trans-Pacific Partnership, there’s little U.S. allies can do but to go along with it and issue the rare dissenting statements, like Macron’s or Trudeau’s, in the hopes that the administration might change in 2020 or 2024 and bring in a president who shares their values."