Watching Saudi Arabia spend hundreds of billions of dollars on sophisticated weapons in the past decade, many friends and foes of the oil-rich kingdom often wondered to what extent it would be capable of using them.

Now, there is an answer. By sustaining nearly a month of intensive airstrikes in Yemen, Saudi Arabia has shown that—from a purely military standpoint—it can lead a lengthy and complicated campaign.

It’s still far from clear that Riyadh will achieve its ultimate goal of rolling back the pro-Iranian Houthi forces that have taken over much of Yemen. The military campaign, the first that Saudi Arabia has led since 1934, has suffered setbacks—most notably anunexpected refusal by traditional ally Pakistan to join the coalition. […]