An amnesty for many illegal immigrants — and especially for those illegal immigrants who came to the U.S. as minors, the first group Obama helped — had broad bipartisan support. Republicans almost all objected to Obama’s doing it himself, without legislation that included other measures such as increased enforcement against new illegal immigration. But a lot of them favored the policy itself.

Nobody has been trying to legislate the convoluted unemployment-benefit scheme Trump just created, on the other hand, and a lot of Republicans and almost all Democrats opposed the payroll-tax cut.

Obama’s policies changed the facts on the ground, too. Once the benefit of an effective amnesty was given to millions of people, it was difficult to take away — especially since it, again, had broad support in the first place. Trying to take it away required administrative steps that could be challenged legally, and so far the courts have kept it in place.

By contrast, it is not clear how widely people will take advantage of Trump’s new programs.