He could have been deported---sent back to his homeland after a 2009 domestic violence conviction (wasn't his wife--the bum hit his grlfriend).
BUT thanks to Obama’s sucking up to terrorism (and illgal latinos), the prez sap-happily decreed that "deportations" are limited only to foreigners who committed “serious crimes”----Obama allowed the Bostom bomber to stay and do his dirty work.
The second bro/bomber ---Dzhokhar Tsarnaev--now in a Boston hospital---was granted "asylum" in 2002.
Yup——DHS’ google-eyes Napolitano has said Obama can pick and choose what laws he can enforce. “Odd” that this was basically the same argument the Canadian jihadist used in court.