Among the many unintended legacies of Barack Obama, one has gone largely unnoticed: the emergence of a novel form of resistance to executive overreach, a check-and-balance improvised in reaction to his various presidential power grabs.

It's the revolt of the state attorneys general, banding together to sue and curb the executive. And it has outlived Obama.

Normally one would expect Congress to be the instrument of resistance to presidential trespass. But Congress has been supine. The Democrats in particular, approving of Obama's policy preferences, allowed him free rein over Congress' constitutional prerogatives.

Into that vacuum stepped the states. Florida and 12 others filed suit against Obamacare the day it was signed. They were later joined by 13 others, making their challenge the first in which a majority of states banded together to try to stop anything.

They did not always succeed, but they succeeded a lot. They got Obamacare's forced Medicaid expansion struck down, though Obamacare as a whole was upheld. Later, a majority of states secured stays for two egregious EPA measures. One had given the feds sovereignty over the generation and distribution of electricity (the Clean Power Plan), the other over practically every ditch and pond in America (the Waters of the United States rule).