Given Trump's claims about moving people to Guantanamo (which is unfeasible on so many levels), this sounds like an opportunistic move by El Salvador. The law

Given Trump's claims about moving people to Guantanamo (which is unfeasible on so many levels), this sounds like an opportunistic move by El Salvador. The law professor cited seems to be judging the offer based on the current legal situation and relies on the meaning of "deportation" applying to this. It seems plausible to me that El Salvador and the US could agree on a flimsy legal fig leaf that redefines the facilities in El Salvador that would be used to house US citizen criminals as US territory with the El Salvadoran prison staff being contracted to operate the facilities. The US would only have to be careful to maintain some formal distinction between citizens and non-citizens "relocated" to El Salvador. This would also establish closer ties between El Salvador and the US, which could benefit El Salvador's owning class economically.