Restricting immigration is a long term investment in America’s future. The golden age Americans remember from the mid 20th century is partly the result of the 1924 immigration act, which cut the foreign born population from almost 15% to under 5% by the 1960s.
As relevant here Carter proposed to make it unlawful to hire illegal immigrants and to impose penalties on companies that did so: https://library.cqpress.com/cqalmanac/document.php?id=cqal77...