David Lin wanted to create a space in China for people to worship as they choose. A pastor from an evangelical Protestant church in California, Mr. Lin told his family that, on many visits, he found a yearning for faith in China. He became active in the “house church” movement of believers who seek to pray independent of the party-state. For this, Mr. Lin has been wrongfully imprisoned in Beijing for nearly two decades. Secretary of State Antony Blinken should use his visit to China, starting Tuesday, to demand Mr. Lin’s freedom.