When you look over the lists of these past executive amnesties, the first thing you notice is that they overlap with foreign crises, presidents having relied on their authority over foreign affairs to “temporarily” legalize illegals here when something hit the fan in their countries of origin. Cuba 1960, the Dominican Republic 1966, Czechoslovakia 1968, Chile 1971, Southeast Asia 1975, Lebanon 1976, Ethiopia 1977, Uganda 1978, Iran 1979, Afghanistan 1980, Poland 1982, Nicaragua 1987, China 1989 — the list reads like a study guide of post-war foreign crises.

Regardless of the president’s authority in foreign affairs, such actions impinged on Congress’s plenary power over immigration policy. Congress grew uncomfortable with the executive’s unilateral ad-hocism, so in 1990 it created something called “Temporary Protected Status” (TPS), in an effort to regularize and subject to statutory control the executive’s exercise of unilateral amnesty…

Be that as it may, another radical departure from past practice is the scale of Obama’s proposed amnesty edict. Even DACA, with its 500,000-plus beneficiaries, is larger than any prior attempt at executive amnesty. (The one exception that advocates point to is the “Family Fairness” edict for spouses and children of people who got amnesty in 1986; the INS commissioner in 1990 estimated that it might apply to as many as 1.5 million illegal aliens, but only about 60,000 received it.)

Scale matters, and at some point quantitative change becomes qualitative.