Saudi Arabia deserves credit for announcing a unilateral two-week coronavirus-related cease-fire in Yemen. But in encouraging its Houthi allies' intransigence, Iran has proven it deserves no American sanctions relief.

Five years of civil war have ripped apart Yemen's already fragile public health infrastructure. Hospitals have been destroyed and medical supplies drained. And even if Saudi forces have shown insufficient regard for civilian lives, Iran's Houthi allies have made a point of disrupting and pillaging aid supplies for their own benefit.

Thanks to the coronavirus, things are set to get a whole lot worse. The epidemic is likely to spread in Yemen without any effective check. Absent adequate healthcare support, vulnerable Yemenis face a particularly grueling challenge in the weeks ahead. The Saudi cease-fire will help here in giving new confidence to nongovernmental organizations and medical professionals to move more freely in Houthi-controlled areas. At the margin, this reduced friction on healthcare services will save lives.

The cease-fire is good for another reason. It shows the increasing nuance of the kingdom's de facto ruler, Saudi Crown Prince Mohammed bin Salman.

Saudi Arabia's involvement in the Yemeni civil war is the crown prince's brainchild. For that reason, the soon-to-be-king has been highly reluctant to alter course in extricating his nation from the intractable conflict. As with his killing of dissident journalist Jamal Khashoggi, the prince has shown a penchant for unnecessary escalation. Those impulses endanger both his critically important domestic reform agenda and broader Middle Eastern stability.

But this announcement shows real moral courage. The crown prince knows his decision will be described as showing weakness. And in that, this decision signals that he is growing into his throne.

Iran has shown a very different calculation here. Its Houthi allies have decried the cease-fire as "just another ploy" and will continue hostilities unless the Saudis admit defeat and withdraw — which will not happen. This zero-sum calculation fits pitch-perfect with Iran's claim of moral leadership in the Middle East.

Where the Iranian hard-liners (those who ultimately control the regime's foreign policy) claim to defend the oppressed under a blanket of pious Shiite theology, they act with wanton disregard for human lives. Just as Iran used the sanctions relief dividends of the 2015 nuclear accord to bolster the Islamic Revolutionary Guard Corps, it tramples its own civilians when they demand basic human rights. And now, as the coronavirus spreads, Iran wants American sanctions relief so it can put more money on its IRGC warhorse. Give me a break.

Saudi Arabia has shown here why it remains an important (if imperfect) American ally. Ayatollah Ali Khamenei has shown that he remains a devoted enemy — not just of America and Yemen, but of humanity at large.