Those who think that either the Constitution or possible negative consequences to the Democratic Party will deter President Obama from acting unilaterally on immigration policy probably still don't understand what makes this man tick.
The main things that drive him are his own interests — whether political or legacy — and his own ideological goals.
The Washington Post is reporting that both Democrats and Republicans "are in a state of high anxiety" over the possibility that Obama will issue an executive order allowing millions of people who entered the country illegally to stay in the United States in contravention of Congress, which clearly hasn't authorized this move.
The Post says both parties, for different reasons, fear that such an action by Obama could negatively impact their prospects in November's midterm elections. Obama's threat — and that's what it is, a threat, because there's nothing positive about his acting lawlessly again, especially for such a nefarious purpose — brings back more un-sweet memories.