As a political move, this may or may not have been a smart thing to say. As a legal move, it seems a non-trivial blunder.
Check it out:

Violating the No-Goad Zone: Last Tuesday, in Nashville, President Obama confidently predicted that no future president would be able to reverse his recent executive amnesty of some 4 million illegal immigrants:

“It’s true a future administration might try to reverse some of our policies. But I’ll be honest with you — the American people basically have a good heart and want to treat people fairly … So any future administration that tried to punish people for doing the right thing, I think, would not have the support of the American people. … It’s true, theoretically, a future administration could do something that I think would be very damaging. It’s not likely, politically, that they reverse everything we’ve done.”