Obama's expansion of presidential power in immigration and healthcare

BLT:  The Blog of the Legal Times reported yesterday that t a House Judiciary hearing yesterday, several constitutional scholars took Obama's recent actions in health care and immigration to task as unconstitutional expansions of presidential power.  (h/t Dan Kowaloski) 

Professor Jonathan Turley of Georgetown Law criticized the steadily expanding power of the presidency since George W. Bush.  With regard to Obama, he stated that the present administration has "an undeniable pattern of circumventing Congress in the creation of new major standards, exceptions, or outright nullification."  Turley accused the Obama Administration of allowing Executive Branch administrative agencies to determine their own jurisdictions. 

I've already noted the reason for the expansion of lawmaking via administrative agency rule changes, which is due to they gridlock and dysfunction in DC have made more substantial  legislative changes impossible.  (For further confirmation of that point, see the recent NYT article about the do nothing, underachieving House of Representatives.)

Regarding immigration in particular, Professor Nicholas Rosenkranz of Georgetown Law criticized Obama for his directing the Department of Homeland Security to deport certain kinds of immigrants (mainly serious criminals) while not deporting DREAMER eligible immigrants, and those with minor children in the U.S. and no criminal record.  Rosenkranz regarded Obama's use of this kind of  discretion as "not within the traditional conception of prosecutorial discretion."  His objection seem to arise from the scale of Obama's instructions, which conservatives have derided as instructing DHS not to enforce the immigration laws on the books, while liberals view it as an exercise of compassion.

Some larger questions that struck me as I read the constitutional law professors objections to Obama's recent actions are:  Is there an inverse relationship between Congress inaction and the expansion of presidential power?  Also, what are the consequences of small-bore lawmaking via incremental administrative agency rule changes in lieu of more lasting legislative change?  My sense on the latter question is that small-bore rule changes are only minor patchwork fixes to the badly broken immigration system and that legislating via rule changes works against the transparency a democracy needs to thrive.