I realize that most candidates don’t have the gonads to do what is actually necessary to win, but if I were running against her I’d run some ads showing just who these “Dreamers” are that are crossing the border, using well-sourced news articles.
There is PLENTY out there, you just have to be ready for the Willie Horton type blowback (i.e., punish the ‘children’ in this case)...which actually works against her, bringing attention to those same ads and her incompetence on the issue.