For Alejandro Chafuen, the gathering this spring at the Brick Hotel in Buenos Aires was as much a homecoming as it was a victory lap. Chafuen, a lanky Argentine-American, had spent his adult life working to undermine left-wing social movements and governments in South and Central America, and boost a business-friendly version of libertarianism instead.

It was a lonely battle for decades, but not lately. Chafuen was among friends at the 2017 Latin America Liberty Forum. The international meeting of libertarian activists was sponsored by the Atlas Economic Research Foundation, a leadership-training nonprofit now known simply as the Atlas Network, which Chafuen has led since 1991. At the Brick Hotel, Chafuen was reveling in recent victories; his years of work were starting to pay off, thanks to political and economic circumstances — but also because of the network of activists Chafuen has been working for so long to cultivate.