First enacted in 1947.
Used repeatedly for quiet removal of spies, migrants, terrorists, mentally ills.
US is a republican form of government, or more concisely a presidential federal constitutional republic.
Where US president is not a Federal employee and democracy is not mentioned anywhere in its US constitution. His secretary does what Congress enacted him to do ... upon order from this Emolument Clause.
Legal residents are not granted "US Person" status until citizenship and has bare minimun rights including First Amendment.
But Mahmoud Khalil didn't violate Free Speech. It is because of who he is. Mahmoud is painted all kinds of things, presumably born in Pakistan under dubious backgrounds, racked all kinds of citizenships, lived in many war-torn areas, attends an ivy league school, has NATO-connections, security clearance(s), and has 19 very rich or prominent lawyers.
My only conclusion is that he lied about who he is, which given media painted enough conclusions leading to one which can be a triple-agent spy (of unknown origin), or of high social order and/or power.
Tenuous but still slated to be expeled. Still am most curious what he did during 2011.
A tough hill to die on to be defending this shady character at this point.
But it isn't about free speech and media aren't being clear on this, purposely or under order.