obama deferred action
Something is wrong when Supreme Court Justices wrestle this way with legal concepts. The problem is clearly not they. The law, regulations, and policies are the problem, as is the inertia that keeps them that way.
The criminal bars for parents applying for deferred action are very strict. Even if there is no absolute bar to a parent's application, immigration officers can still deny it for "discretionary" reasons -- in other words, if something about the applicant raises concerns about her continued presence in the US.
We are a long ways from fixing our broken immigration system if our only cause for celebration is relief from deportation in the interior of the nation, while we feed the deportation machine at the border.