American military: If we want to contain Russia, we need to spend more.

One day after Slate published my column on why the United States needs a more capable and more expensive military, a group of terrorists launched a series of coordinated attacks in Paris that left dozens of innocent people dead and wounded. Spending more on the U.S. military will not mean the end of mass-casualty terror attacks, and anyone who tells you otherwise is mistaken. But it is also foolish to believe that such attacks would cease if the U.S. and its allies were to withdraw from the wider world.

Threats that emerge in one part of the world can quickly spread to another. There is no going back to a world in which we can wall ourselves off from foreign threats, if there ever was such a world. Whether we like it or not, we have a stake in the success of Libya and Yemen, both of which are in the midst of bloody civil wars that have been overshadowed by the Syrian conflict. Jihadist groups feed on the chaos and dislocation caused by these conflicts, and the violence that results has a way of spilling over into Western societies. When states collapse in West Africa, severe epidemics like the Ebola outbreaks of 2014 grow more likely, as does the prospect of their spread to cities like London and New York. When a devastating earthquake hits Haiti, and when a tsunami leads to tens of thousands of deaths in the Indian Ocean rim, families are uprooted, some of whom then become migrants looking for a home. If a nuclear war were to break out between Pakistan and India, the consequences for the world, and for the environment we all share, would be dire. That is why the United States must concern itself with more than defending the homeland against invasion, or avenging Americans killed in terror attacks. We have a vested interest in building up the defense and governance capabilities of vulnerable countries around the world, and in ensuring that minor conflicts don’t become major conflagrations.

Of course, the U.S. can’t be everywhere and do everything, nor should it. But because the U.S. is an affluent, populous, and dynamic society situated far away from rival powers, it is in a unique position to make selective investments that can have a disproportionately positive impact on global security. No one is calling for the U.S. to double its military spending, or even to return military spending to the 5 percent or more of GDP that was common in the Cold War era. Serious advocates of higher military spending are focused on far more modest goals.

Read the full article at Slate.