One of the most memorable lines of President Trump’s address to a joint session of Congress last week was his declaration that “the time for trivial fights is behind us.”

The morning after the address, I argued that any move on Trump’s part to undermine that claim would taint the country’s memory of his widely-celebrated speech. Here we are, less than one week later, and the president was back to taunting Arnold Schwarzenegger over Twitter by Saturday morning.