Michael Greve points out that:
In two noteworthy instances—the President’s “deferred action” immigration plan and, as of yesterday, his “clean power” plan—the federal courts have told the administration that it will have to wait. The technical term is a “stay.”
The legal effect of a stay order is to preserve the legal status quo, pending a resolution on the merits. But what’s the real-world effect on a “can’t await” administration? It depends. ...
For reasons explained in an earlier post the EPA cares not one whit about the legality of its rule. Should it care about the Supreme Court’s stay order? The White House press statement on the order explains:
Even while the litigation proceeds, EPA has indicated it will work with states that choose to continue plan development and will prepare the tools those states will need. At the same time, the Administration will continue to take aggressive steps to make forward progress to reduce carbon emissions.
In short: no. EPA will continue doing what it has been doing since long before the rule was published, and ever since: promise “cooperative” states and industries the blue sky, while threatening the laggards with dire consequences.
Can you imagine the howls of outrage that would be rising from the DC Establishment if a GOP President were to so blatantly defy a Supreme Court order?
Unilateral executive action because Congress won't act + Defying courts orders to stop doing so = The end of the rule of the law.
Here's a post by Jonathan Adler expressing similar concerns.
And here's an Adler post with legal analysis of the Supreme Court stay.