Back in March, when one of the key topics was a no-fly zone over Ukraine, U.S. Defense Secr. Lloyd Austin rejected the idea flat out because it would mean having to shut down Russia's air defenses on the ground, and some of those air-defense systems are in Russia. "A no-fly zone means that you're in a conflict with Russia," he said. "So from a U.S. perspective, our position remains that we're not going to do that." Czech PM Petr Fiala said at the time that a no-fly zone would mean going to war with Russia and that Nato is a defense alliance. Such a debate is coming back because of the affirmation of the U.S. last week that it's okay for Ukraine to use weapons supplied by Washington to attack Russian-occupied Crimea. The U.S. argument is that Crimea is Ukrainian territory and that any target Kyiv chooses to pursue on sovereign Ukrainian soil is by definition self-defense. Russia of course doesn't see it that way. Fiala hasn't yet commented on where his government stands on the issue. [ Czech Republic United States of American secretary Biden administration Politico ]