This isn't new. The US has been regularly doing these kinds of tests since the 90s and two took place last year. I'd be surprised if this was a specific response to Russia instead of something that's been planned for months.
> Russian lawmakers announced their intention to revoke the ratification of the Comprehensive Nuclear Test Ban Treaty.<p>> Deputy Foreign Minister Sergei Ryabkov said last week that Moscow will continue to respect the ban and will only resume nuclear tests if Washington does so first.<p>> The U.S. conducted a high-explosive experiment at a nuclear test site in Nevada hours after Russia revoked a ban on atomic-weapons testing<p>> A bill will go to the Russian upper house, the Federation Council, which will consider it next week. Federation Council lawmakers have already said they will support the bill.<p>That's probably the most biased and internally incosistent article about nuclear testing I've seen.
Can we only title things like this a <i>sub-critical</i> test<p>I realize the hacker news headline accurately reproduces the incredibly dangerous and clickbaity Fox news headline. But it's incredibly misleading. Even if Fox News won't do better - can we? So then the title would appear:<p><i>"US conducts [Subcritical] nuclear test in Nevada hours after Russian move to revoke test ban (foxnews.com)"</i>