Earlier quoted context omitted.
It's not protectionism. Most of that manufacturing is not moving back to the U.S., it's moving to U.S. allies like Vietnam or Mexico, that would also be called third world countries. It really is what it says on the tin. It's a risk for the U.S. to be economically dependent on a state whose government does not share American values, and that is threatening its neighbors with invasion.
Vietnam and Mexico are not "US allies"
Mexico is the USA's second largest trading partner worldwide. Exports of goods and services to Mexico support an estimated 1.1 million jobs (Department of Commerce). Mexico is also the second largest source of foreign crude oil to the USA, and the top export destination for US petroleum & natural gas. The US-Mexico-Canada agreement (USMCA) entered force in 2020, replacing NAFTA. The countries have a variety of complex ties. There are other treaties and areas of cooperation too, such as the International Boundary and Water Commission (IBWC). A security cooperation agreement called the Bicentennial Framework for Security, Public Health, and Safe Communities went into effect in 2021.
As for Vietnam, the US and Vietnam established a bilateral trade agreement in 2001. The US provides maritime security assistance to the country through the Maritime Security Initiative, Cooperative Threat Reduction Program, and through foreign military financing. US transferred Coast Guard cutters to Vietnam in 2017 and 2020 to bolster its law enforcement capabilities.
Those sound like alliances to me, but I'm interested to hear what other definition you're using.