"The wise man builds bridges; the fool builds walls." That was the sentiment splashed all over recent Chinese editorial pages when the United States imposed 25 percent tariffs on some $50 billion of Chinese goods. Unfortunately, that isolationist approach extends beyond U.S. trade policy in ways that are not just foolish, but also unethical — and they are depleting what's left of the West's moral authority.

When it comes to trade, China of course immediately retaliated with its own tariffs on $50 billion of U.S. imports, just as Canada, the European Union and Mexico are retaliating for U.S. tariffs on steel and aluminum imports. Such disputes, if they continue to escalate, will hurt people all over the world — not least U.S. consumers, businesses and workers.

Worse, in recent months, U.S. President Donald Trump ordered a zero-tolerance immigration policy that treats all adults crossing the border illegally — a misdemeanor — as if they were violent criminals. That has meant referring even asylum seekers for prosecution and, most controversially, taking away their children to be detained separately. More than 2,300 minors have been placed in shelters. Succumbing to political pressure, Trump signed an executive order stating that parents and children would be detained together. But that order itself may be illegal; while a federal court considers the issue, prosecutions will continue and there is no plan in place for reuniting families that have already been divided.