To double-down on this a bit: the Trump Administration's policy of separating families at the border is very unpopular. (Roughly 30% in favor, 60% opposed.) It's not like, say, the travel ban, where opposition was mostly limited to Democrats.https://twitter.com/micahcohen/status/1008723815134789633 …
The question also is narrowly formulated in that it focuses on separation after crossing border, whereas there's a number of reports of that happening without "illegal" border crossing first...