After 2,700 years, Iranian troops are back in Crimea, this time to help Russia crash drones into Ukrainian targets.

(Originally published Oct. 21 in “What in the World“) Troops from Iran haven’t set foot in Crimea since the forces of Darius I attacked the Scythians there in 500 BC.

So confirmation by Washington that Iranian troops are in Crimea training Russian forces how to use kamikaze drones supplied by Tehran provides a new potential pretext for expanding the war against Russia’s invasion of Ukraine. With Iran now technically entering the war directly as a combatant, the question is whether the North Atlantic Treaty Organization will retaliate against Iran militarily. It also raises the question of whether NATO would now be justified in sending its own forces into Ukraine, since it doesn’t recognize Russia’s 2014 annexation of Crimea.

Of course, from Moscow’s perspective, the answer is “no.” Moscow considers Crimea Russian territory. And anyway, those drones aren’t Iranian, it says. After the United Nations Security Council called a closed-door meeting to discuss whether Russia had violated international sanctions against Iran by buying the drones, Russia insisted the drones were made in Russia and denied buying them from Iran. Iran has also denied supplying Russia with drones. But Ukraine says it has shot down more than 200 of the drones, which it says are Iranian-made Shahed-136s. Ukrainian military photos of crashed drones shows them bearing painted markings in Cyrillic.

The chief of U.S. naval operations warned Wednesday that China could invade Taiwan this year. Adm. Michael Gilday said at an event in Washington, D.C. organized by the Atlantic Council think tank that he couldn’t rule out a Chinese invasion much earlier than anticipated. “What we’ve seen over the past 20 years is that they have delivered on every promise they’ve made earlier than they said they were going to deliver on it,” he said.

Last year, the now-retired head of the U.S. Indo-Pacific Command warned that China might attempt to reunify Taiwan by force within the next six years, or by 2027. That timeline appears now to have become baked into hawkish discussions in Washington about China’s intentions for what it considers a renegade province.

Chinese President Xi Jinping triggered renewed speculation on Sunday when during an address to delegates at China’s 20th National Congress of the Chinese Communist Party in Beijing he reiterated China’s longstanding position that, while it would strive for Taiwan’s peaceful reunification, “we will never promise to renounce the use of force, and we reserve the option of taking all measures necessary.”

Inspired by Ukraine’s successful resistance against Russian conquest, the United States has adopted a so-called “porcupine” strategy for defending Taiwan from potential invasion. That strategy entails supplying Taiwan with a massive arsenal of defensive weapons that would allow it to fend off Chinese forces until the U.S. could come to its aid. Last month, the White House approved a $1.1 billion weapons sale to Taiwan as part of that. It’s unclear whether U.S. troops will venture to Taiwan for training purposes.