How to fix the ‘lack of assimilation’ problem with immigrants today?

How to fix the ‘lack of assimilation’ problem with immigrants today?  After the 1880’s, at points of entry to America, immigrants were given Anglicized names, cities offered adult night courses in English and free elementary schools for children, ladies paid calls on families to preach the virtues of naturalization, the D.A.R. produced loyalty lectures to inculcate the ‘spirit of Americanism’ and lastly, acceptable cultural ideas (typically conservative) taught people to “use it up, wear it out and make it do.”  When a child today pledges allegiance to ISIS, as just occurred in one of our schools – what should we really do as opposed to merely segregating the offender?