When it came to the foreign policy discussion at Tuesday night's Democratic presidential primary debate, there was only one standout candidate: Pete Buttigieg.

He was calm but resolved. America's word matters greatly not simply for its moral essence, but for the strategic understanding that word proffers in others. The understanding of enemies that America is challenged at one's peril. The understanding of allies that America is a force to align with in pursuit of a better future. The understanding of neutral nations that America is a nation to respect.

Buttigieg was right. What President Trump has done in Syria over the past two weeks is to undercut the moral and strategic credibility of America's word. Buttigieg was also right about something else, something too many on the Left and Right ignore or pretend to ignore: the basic truth that there is a foreign policy middle road between endless war and total withdrawal from the world.

That doesn't mean Buttigieg has all the answers on foreign policy.

Of course, not. As a Democratic candidate more predisposed to spending on domestic programs than on national security, his plans deserve close scrutiny. Chinese anti-ship missiles and Russian air defense bubbles won't be defeated by a larger foreign aid budget and nicely tinged calls to peace. And it must be said that Democrats do not have as supreme a record on foreign policy as they presently wish to presume. Trump's predecessor was weak on China and weak on Russia. Those nations rose in threat to America thanks to the space President Barack Obama gave them.

Still, Buttigieg deserves credit for speaking plainly about the importance of American leadership. Without that leadership the world would be poorer, less free, and less safe.

Trump is newly vulnerable here, Buttigieg showed why.