Americans have united before to defeat an external enemy and we can again

We live in a time of bitter divisions. Today, even the wearing of masks has become a partisan question.

Yet, as this Memorial Day weekend reminds us, this country has united before to meet external threats. The calamity that has been wrought by the coronavirus is the result of an external attack — this time by a virus rather than an armed enemy. It too should be a time of national unity, of rallying together to share the sacrifices, to help one another through the crisis, and to rebuild the...