"Certainly, Supreme Court rulings have higher authority to set precedent than any other court.

But still they are just law, and there are ways to overturn them, modify them, supercede them, or ignore them. Believe me, there are plenty of Supreme Court rulings from the 1800's that folks today would think are pretty silly."

The executive does have the power to choose not to enforce- another way to say, ignore a Supreme Court ruling. But to say they are "just" laws, in which a country is Ruled by Law is a bit silly. An executive order which is deemed unconstitutional by the Supreme court- has no power- people may choose to follow it (because they want to or because they think the president is really swell person, but it's not legally binding). To continue or insist on an exective order be followed after it's been deemed unconstituational, could be grounds for a impeachment- the president would not be upholding the constitutions. Of course, impeachment is something done by Congress, so Supreme Court has no direct power over the President and could be easily ignored by Congess. And of course, the order would first need to be contested and evenually brought to the supreme court first, before it could have any decision about it.