After a campaign denigrating Muslims as “sick people,” blaming the children of Muslim Americans for terrorism, and promising to “shut down” Muslim immigration, and mere days after his inauguration, President Donald J. Trump banned the nationals of seven majority-Muslim countries from...

Presidential abdication in immigration law has long been synonymous with the perceived nonenforcement of certain provisions of the Immigration and Nationality Act. President Obama’s never-implemented policy of deferred action, known as DAPA, serves as the prime example in the literature. But...