This week, as President Trump comes out in support of a bill that seeks to halve legal immigration to the United States, his administration is emphasising the idea that Americans and their jobs need to be protected from all newcomers — undocumented and documented. To support that idea, his senior policy adviser Stephen Miller has turned to a moment in American history that is often referenced by those who support curbing immigration: the Mariel boatlift of 1980. But, in fact, much of the conventional wisdom about that episode is based on falsehoods rooted in Cold War rhetoric, writes USSC visiting scholar Julio Capó.