fta: Mass protests and anti-government violence have left dozens dead. Russia is deploying 3,000 paratroopers after Kazakh security forces were overrun. The largest city, Almaty, looks like a warzone. To appreciate why Russia is willing to deploy troops to Kazakhstan, it's critical to understand the depth of Russia's vital national interests inside the country. This isn't just any former Soviet republic. It's almost as important to Russia as Belarus or Ukraine.

First, Russia and Kazakhstan have the largest continuous land border on planet earth. If Kazakhstan destabilizes, a significant fraction of the country's 19 million residents could become refugees streaming across the border. Russia is not willing to let that happen.

Second, roughly one-quarter of the population of Kazakhstan is ethnic Russians. Kazakh nationalists are overwhelmingly Muslims, who resent the Orthodox-Christian Russian minority. Russia believes that civil war would entail a non-trivial risk of anti-Russian ethnic cleansing.

Third, the Baikonur Cosmodrome in Kazakhstan was the heart of the Soviet space program. Russia still uses it as its primary space-launch facility. The Vostochny Cosmodrome in Russia's Far East will lessen that dependence, but it still isn't complete.