Following President Obama’s ambitious executive order on immigration — unprecedented not in subject matter but in scope and ambition — we are left to pick through the wreckage of law and precedent.

Obama’s action was a substitute for legislation — imposed precisely because legislation he favored did not pass. So what issues might have been raised during the legislative debate Obama preempted?

There is the matter of arbitrariness. Obama’s defense of his action is sweeping and unqualified. We are not a nation that “accepts the cruelty of ripping children from their parents’ arms.” Unless, of course, they arrived less than five years ago. A moral rule is apparently bounded by a bureaucratic line. And an appeal intended to put Republicans on the defensive also puts Hillary Clinton on the spot. One possible news conference question: “Madam Secretary, if an American president has the unilateral power to remove people from the shadows, why not people who arrived during the Obama years?”

There is also the matter of implementation. The U.S. Citizenship and Immigration Services processes about 4 million cases of all kinds each year. Now as many as 4 million applications — involving documentation of the arbitrary five-year limit — will be added over an indeterminate period of time. The office, which is currently overwhelmed, has six months to prepare for the onslaught. Opportunities for fraud and exploitation will certainly multiply. Will the lines for services provided to legal immigrants lengthen? An actual legislative debate might have clarified these challenges, particularly in light of the administration’s Obamacare and Veterans Affairs debacles.

The American political system not only lacks action; it lacks deliberation. On immigration, Obama has provided the first by circumventing the second — and provided a precedent for other presidents to avoid deliberation on other matters. During campaign-like events, Obama has made a strong case for immigration reform legislation, employing arguments that could have been made (and were) by George W. Bush. He has not made a case for short-circuiting the legislative process, except for noting that Congress has not acted in the way he wants, on the time line he prefers. It is an Augustinian ploy, made from a Jimmy Carter-like political position.

But — and this is perhaps the most significant conjunction of its kind since Kim Kardashian’s — Obama’s action shows the power of even a weakened president to influence a public debate. After all of the important legal, practical, political and procedural objections to Obama’s executive order, he has called attention to a fundamentally sympathetic group of human beings caught in an unjust and unworkable system. People who come to America to construct a better life, sometimes at great personal cost and risk, are not common criminals, even when they lack documentation. They (and all of the rest of us) deserve an immigration system that honors both the rule of law and human dignity. Our current one does not.

Obama’s willful revision of that law has problems of its own. It falls short on visas for high-tech workers. It provides no path to citizenship. In the most cynical (and most likely) interpretation, it uses undocumented workers in a vast political ploy.

But, no Republican running for president — or, at least, no Republican with serious prospects of actually becoming president — can simply say that the group that Obama has registered will be summarily deported. This would be impractical, immoral and politically self-destructive. Any future Republican proposal for comprehensive immigration reform will need to include a provision that deals with this humanitarian concern. Obama’s action — however currently controversial — will not be entirely undone.

This is already evident in the serious Republican response to the executive order — from a strengthened and disciplined Republican congressional leadership — which has focused on confronting Obama’s overreach rather than scapegoating people his action is designed to help. Former Florida governor Jeb Bush placed his opposition to Obama’s power grab within the context of a call for comprehensive reform — the only position that allows the GOP to confront its long-term demographic challenges.

Obama’s action on immigration creates a situation similar to health care. Obamacare was passed in a partisan march, implemented incompetently and sold to the public (as we know from professor Jonathan Gruber) in a deceptive fashion. But Republicans running for president will still need to propose a market-oriented alternative for the people currently getting health coverage under Obama’s plan.

This may be Obama’s very mixed presidential legacy. His methods are controversial, divisive and sometimes disturbing, and they often failed; his goals have shifted the American political debate.

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