President Trump on June 12 in Singapore. (Evan Vucci/AP)

Last weekend, in the name of national security, the president of the United States, who is sworn to protect our country, dangerously undermined it. Using a pre-World War II model of “America First,” he acted to isolate us from our allies by demeaning them and lying about the world order that we built [“In wielding power, Trump is increasingly going it alone,” news, June 12]. The assumption that international relations might return to a time of winners and losers plays to urges that lurk inside all of us — urges that are easily inflamed and not so easily tamed.

Although it took thousands of years to learn the benefits of win-win dialogue, volcanic eruptions of uncivil evil remind us of how fragile those lessons can be. The threat from within that the president poses can be remedied only by the voting public. The challenge facing his opponents is that the case for civilized dialogue is harder to make than his letting loose calls to the fear of losing.

Herbert S. Gross, Rockville