MAD DUCK: President Obama bans oil drilling in large areas of Atlantic and Arctic oceans.

Obama used a little-known law called the Outer Continental Shelf Lands Act to protect large portions of the Chukchi and Beaufort seas in the Arctic and a string of canyons in the Atlantic stretching from Massachusetts to Virginia from oil exploration and the potential for spills.

The announcement by the White House late in the afternoon was coordinated with similar steps being taken by Canadian Prime Minister Justin Trudeau to shield large areas of that nation’s Arctic waters from drilling. Neither measure affects leases already held by oil and gas companies and drilling activity in state waters.

White House officials said the withdrawals under Section 12-A of the 1953 act used by presidents dating to Dwight Eisenhower cannot be undone by an incoming president. It is not clear if a Republican-controlled Congress can rescind Obama’s action.

How is it possible for one President’s signature to mean more than another, or that Congress suddenly can’t pass new legislation superseding old legislation?

In any case, it’s long past time for Congress to start reclaiming the powers it has ceded to the Executive — but don’t hold your breath.