A democracy dies by a thousand cuts. A particularly deep one may come later this week, administered by none other than Barack Obama.

As has been widely reported for months, the president plans to make "changes to the immigration enforcement system" that "could offer legal documents to as many as five million immigrants in the country illegally." And as New York Times columnist Ross Douthat has provocatively and persuasively explained — often in painstaking and illuminating exchanges with Obama's defenders — those changes would constitute an unprecedented and quite likely unconstitutional power grab, in which the head of the executive branch claims "prosecutorial discretion" to ignore and even actively contravene laws passed by Congress.

Now let me be completely clear: I'm all in favor of immigration reform that includes a path to citizenship for immigrants already living in the United States. I think the refusal of the House Republican majority to pass an immigration reform bill — or, really, to do much of anything at all — over the past two years is a disgrace. I fear that with the GOP now in control of the Senate as well, Washington may well grind to a standstill — and that this heightened level of dysfunction in the nation's capital may well redound to the benefit of Republicans, who use disgust at Washington as fuel for their anti-government furies.

That's bad.

But what Obama is proposing is worse. Much worse.

The rule of law is far more about how things are done than about what is done. If Obama does what he appears poised to do, I won't be the least bit troubled about the government breaking up fewer families and deporting fewer immigrants. But I will be deeply troubled about how the president went about achieving this goal — by violating the letter and the spirit of federal law.

To grasp precisely what's so galling about Obama's proposed actions, it's necessary to reflect on the nature of executive power and its permanent potential to become despotic.

Executive power can be reined in, as the U.S. Constitution attempts to do. But there are always limits to how much a president can be restrained, and not just because, or not simply because, executives are prone to maximize their own power. As political thinkers from Aristotle to John Locke and the American constitutional framers have recognized, there will be situations in which the common good demands and requires that the executive go beyond the letter and even the spirit of the law. In these extreme or emergency situations — situations in which an existential threat poses a grave danger, with the survival of the political community itself at stake — the executive's extralegal decisions effectively become the community's higher law.

Probably the clearest example from American history is Abraham Lincoln's 1861 suspension of habeas corpus, defiance of the chief justice of the U.S. Supreme Court (who denounced Lincoln's actions as unconstitutional), and subsequent arrest (without charge) of pro-secessionist Maryland state legislators who appeared poised to condemn the suspension and vote to join the Confederacy.

Was Lincoln acting like a tyrant, as Maryland native John Wilkes Booth and many other critics of the time contended? You bet he was. And it's a good thing, too. Had Maryland seceded, Washington would have been surrounded by enemy armies and the South almost certainly would have won the Civil War quickly and decisively. Extralegal action was required to keep that from happening.

The willingness to break the law in order to preserve the common good is a mark of statesmanship at its peak. But it is also perilous for everyone involved — not least the statesman himself, who relies on his own judgment alone to determine whether the circumstances are grave enough to justify his transgressions.

Was the judgment correct? Or might the crisis have been averted without it? Those crucial questions are often unanswerable until the emergency has ended and executive law-abidingness has been restored. At that point, the statesman will either be judged a hero for his temporary embrace of despotic tactics — or he will be condemned as an enemy of ordinary decency who used the crisis as a pretext to aggrandize his own power. There is often no way to reach a final judgment while the crisis is still underway.

That's what makes it so hard to judge the extralegal actions of George W. Bush and other senior members of his administration. After the Sept. 11 attacks, the administration claimed that the nation faced potentially mortal threats to its national security from sub-state actors who might seek to detonate weapons of mass destruction in American cities. That threat — a perpetual ticking-time-bomb scenario — was then used to justify extralegal actions (including torture of terrorism subjects) to thwart those potential attacks.

Critics have demanded that senior Bush administration officials be brought up on war crimes charges for authorizing torture. But such judgments can only be fairly rendered once the state of emergency has come to an end. Only then will we be capable of judging if the threat to the common good was sufficiently grave to justify breaking the law.

But what if the war or terror — and the state of emergency that goes along with it — never ends? That prospect should send a chill down the spines of civil libertarians everywhere, because it suggests that we may have entered an era in which circumstances demand that the executive be granted extralegal authority on a semi-permanent basis.

It is within this ominous context that President Obama's proposed actions on immigration need to be evaluated. Compared with torture, rendition, and the extrajudicial use of surveillance and even deadly force against American citizens, Obama's efforts to help illegal immigrants can seem benign and even trivial. But that's precisely the point. No matter how you feel about Bush's actions, up until now, executive transgressions of the law have been made in the name of protecting the common good from a grave threat in a time of emergency.

What is so galling about the president's pending circumvention of federal immigration law is that the White House hasn't even attempted to justify it on grounds of necessity — no doubt because any effort to do so would be risible. The nation obviously faces no immigration emergency that could possibly justify the kind of extralegal action that Obama is contemplating. Cultivating a new constituency for the Democratic Party certainly doesn't rise to that level, but neither does a big-hearted attempt to stop often cruel deportations of individuals and families residing in this country illegally.

Have we really gotten to the point where the executive can ignore and even violate, on the absurdly open-ended basis of "discretion," the express intent of a federal law he is constitutionally empowered to execute — not because of an emergency, not because of a national threat, but merely because he wants to be a nice guy?

As Douthat notes, such discretion could easily be used by a future Republican president to rewrite the federal tax code by fiat. But really, it could be used by any president of either party to do anything at all.

Maybe that's not a problem. Maybe the rule of law is passé. Maybe democracy's more trouble than it's worth. Maybe we'd be happier with an elected monarchy in which the legislature merely played an advisory role in making and execution of laws.

I just wish that we'd be honest about the fact that our system appears to be evolving in that direction — and that liberals, in particular, would admit that Barack Obama appears prepared to make an important contribution to bringing it about.