If the POTUS goes around Congress with an illegal Executive Order, it will be easily overturned by the Supreme Court in my opinion.
I wouldn't bet on that. Look what "conservative" Justice Roberts did with the un-Constitutional Obamacare just because "he didn't wnat to be the one to strike it down", not that it violated the law. Pure personal "feelings" over the rule of law.
In addition, Obama may get to appoint TWO far left Supreme Court justices this term (like the previous two) which would shift the balance to very liberal. Then just about anything he does will be upheld.
Elections have consequences. Thanks Amerika.