Apple is beginning to bring its semiconductor manufacturing supply chain back to the United States. Nearly all of the most advanced chips are made in Taiwan, which China has threatened to annex. Concentrating chip supplies on an island that could be invaded, or face steep U.S. tariffs from Trump, is a big risk to Apple’s business. To find out how far the company still has to go, WSJ reporter Rolfe Winkler visited several of the company’s suppliers including TSMC, ASML and Foxconn in the