Dr. John Tanton, a small-town ophthalmologist who founded or fostered the nation’s leading anti-immigration groups, which have helped shape President Trump’s hard-line immigration policies, died on Tuesday in Petoskey, Mich. He was 85.

His death was announced by the Federation for American Immigration Reform, or FAIR, which he started four decades ago with the aim of reducing the number of immigrants to the United States. The cause was not given, but a funeral home obituary in Michigan said he had struggled with Parkinson’s disease for 16 years.

Other groups that Dr. Tanton either directly founded or provided with seed money and logistical support include the Center for Immigration Studies and the Immigration Reform Law Institute, both in Washington, and NumbersUSA, in Arlington, Va.

He also started groups dedicated to making English the official language of the United States and a publishing arm that put out the journal The Social Contract, as well as books by leading opponents of immigration.