Amalija Knavs, mother of the former first lady and who died last January, joined Uncle Sam's lands from Slovenia via a legal mechanism in force in the United States since 1965. This mechanism allows American citizens to bring their parents, or their minor children, to the country, avoiding the usual administrative burden to obtain a visa.
During his presidency, Donald Trump accused this mechanism of allowing “chain migration” He had also defended a bill which limited sponsorship only to minor children of American citizens as well as to spouses.