US troops just paraded along the Russian border. Is that as insane as it sounds? (Source vox.com)

On Wednesday, the US Army did something that seemed, and maybe was, dangerously provocative: it paraded soldiers and armored vehicles from the Second Cavalry Regiment in the Estonian town of Narva, just 900 feet from Russia’s border. The Washington Post’s Michael Birnbaum, reporting the incident, explains, “Narva is a vulnerable border city separated by a river from Russia. It has often been cited as a potential target for the Kremlin if it wanted to escalate its conflict with the West onto NATO territory.” There is a logic to this sort of demonstration, which is surely meant to show Russia that the US is sincerely committed to the defense of Estonia, which is a member of NATO. In other words, it is meant to deter Russia from starting a Ukraine-style conflict in Estonia, which could plausibly spiral into World War Three. At the same time, such a demonstration is also dangerous, as it risks being misinterpreted by Moscow as an act of aggression and thus making war more likely. Estonia and other Baltic countries, like Ukraine, used to be part of the Soviet Union and have significant Russian or Russian-speaking minorities. Europe has feared that Vladimir Putin might attempt some version of what he did in Ukraine, stirring up pro-Russian sentiment, arming separatists, or even overtly invading. President Obama took this seriously enough to travel to Estonia in September to give a speech pledging that the US would defend the country against Russian aggression. This isn’t just scary because it would be bad to repeat the Ukraine crisis in another country, though it surely would. Estonia is a member of NATO, which means that all other members are committed to help defend it in a war. That includes the US and most European countries, two of which (France and the UK) are nuclear armed. If Putin were to invade Estonia tomorrow, it would spark war between several nuclear powers, and that would be a global catastrophe. Putin does not want World War Three, though, so he’s not going to simply invade Estonia. What’s more plausible, and in many ways scarier, is the possibility that he could attempt smaller and more indirect provocations of the sort he deployed at first in Ukraine. Putin could read The US Army parading on his border as a threat of American aggression or outright invasion. That would make things substantially more dangerous.