In the 1950s, President Eisenhower launched the largest U.S. deportation effort.

In the 1950s after being elected President Eisenhower was shocked to learn that do many illegal aliens from Mexico were in the U.S. and launched the largest mass deportation program ever, now widely known as “Operation Wetback”. That, of course, was not it’s official name; however, supporters of mass illegal immigration continue to use the name to demonstrate the supposedly “racist” program of enforcing U.S. laws.

https://en.wikipedia.org/wiki/Operation_Wetback

https://www.history.com/news/operation-wetback-eisenhower-1954-deportation