The Biden administration is diverting Patriot missile systems to Ukraine and away from the foreign customers for whom the systems were originally intended. The air defense system has proven its worth in helping Ukraine defend against Russia’s daily air attacks. That onslaught deliberately targets civilians and nonmilitary infrastructure including apartment buildings and shopping centers. The United States is right to prioritize Ukraine’s defense.

Yet the need to divert the Patriots underlines a broader concern we have long emphasized: America’s military-industrial base is now painfully inadequate. Allies who will now suffer delays to Patriot deliveries will probably include the United Arab Emirates, Qatar, and South Korea. Taiwan, fortunately, will be exempt. That’s important amid the growing threat the island democracy faces from China.