The Lower Floor - NYTimes.com I found last week's Supreme Court argument in the Arizona immigration case utterly depressing, and I've spent the intervening week puzzling over my reaction. It's not simply that the federal government seems poised to lose: unlike the appeals court, the justices appear likely to find the heart of Arizona's mean-spirited "attrition through enforcement" statute, S.B. 1070, permissible under federal law. Poring over the argument transcript and the briefs, what finally came through as most deeply troubling was this: the failure of any participant in the argument, justice or advocate for either side, to affirm the simple humanity of Arizona's several hundred thousand undocumented residents. Both facts and logic tell us that this is a varied population. Different reasons, different routes and different times brought these individuals to Arizona. Half the adults among them hold jobs. Many are parents of American-born citizens of the United States. An untold number, while not possessing the right papers, are also not now deportable under our byzantine immigration laws. But whoever they are and whatever their stories, all are now likely to become what Arizona intended them to be when it enacted the law two years ago: hunted. Under the portions of S.B. 1070 that the lower federal courts have blocked, it is a crime, subject to imprisonment and a fine, for an "unauthorized alien" to seek work, a "criminalization of work" that has no counterpart in federal law. Police officers must determine the immigration status of anyone they stop if they have "reasonable suspicion" that the person is "unlawfully present in the United States." A violation of the federal alien-registration statute is deemed a state criminal offense. Arizona police may arrest, without a warrant, anyone whom they have probable cause to believe has committed "any public offense that makes the person removable from the United States." As the argument proceeded, it was all trees and no forest, the justices toying with first one section and then another. How long does it take to check the immigration status of someone whom the police have detained? "Two hours?" asked one justice. "Two days?" another wondered. Only 10 minutes or maybe 11, Paul D. Clement, representing Arizona, answered reassuringly. O.K., not so bad, on to the next section. I was reminded of the blind men and the elephant in the old fable. No one saw the statute whole. The observation by Solicitor General Donald B. Verrilli Jr. that federal immigration law is "exceedingly delicate and complex," replete with foreign policy implications and not amenable to blunderbuss treatment by each of 50 states, was met with skepticism, as was his insistence that the federal government needs to be able to set its own enforcement priorities. So you're saying the government has a legitimate interest in not enforcing its laws? Justice Anthony M. Kennedy asked. Justice Antonin Scalia took a "why even bother" approach, asking the solicitor general: "Are you objecting to harassing the people who have no business being here?" Many casual followers of this case, State of Arizona v. United States, no doubt assume it has something to do with the rights of undocumented immigrants. As the argument made abundantly clear, it doesn't. The question, rather, is which of two sovereigns, the United States or the state of Arizona, has the right to make the immigrants" lives difficult. Federal preemption is a doctrine about structure, not rights. Preemption sets a federally designated floor below which the states aren't permitted to sink. The problem is that when it comes to immigration, the floor is getting lower all the time. The most telling moment came early in Mr. Clement's description of the Arizona law, when he said: "The federal government doesn't like this statute, but they are very proud of their Secure Communities program." Secure Communities, of course, is the program under which the federal government commandeers local law enforcement officials, including those with their own contrary enforcement priorities, into the process of identifying deportable aliens. It requires local police and prison officials to provide to the F.B.I. the fingerprints of anyone arrested, to enable federal immigration authorities to then check the prints against immigration databases and, in the case of a match, to take custody of the person upon release. The program began late in the Bush administration. Despite mounting objections from state and local officials, the Obama administration has pursued Secure Communities vigorously as a tool in meeting its goal of 400,000 deportations a year. Immigrants with no criminal record have been deported after minor traffic violations. While the administration has said repeatedly that its priority is deporting those convicted of serious crimes, the deportation culture is so ingrained and the undocumented are so demonized among those who enforce the law that resistance by officers of the Immigration and Customs Enforcement agency has become a serious obstacle to conforming the agency's performance to the president's stated priorities. So Mr. Clement, the Bush administration's last solicitor general, was certainly on to something when he suggested that Arizona was simply following Washington's lead. Indeed, he and his successor, Mr. Verrilli, seemed engaged in a verbal arms race. The federal government's brief offered a startling description of what the government was doing on the Arizona-Mexico border in the spring of 2010, when the Arizona Legislature passed S.B. 1070: 4,000 Border Patrol agents stationed there, a 40 percent increase since 2005; 40 aircraft on patrol; 305.7 miles of border fence completed. The description was aimed at showing that the Feds were on the case and that Arizona's law was simply superfluous. Perhaps so, but I read this account as the chilling self-description of a powerful nation obsessed with imaginary enemies. "Before I built a wall I'd ask to know/ What I was walling in or walling out," Robert Frost wrote. We have walled ourselves in, whether by Arizona's hand or Washington's or both. The Supreme Court will tell us if the difference matters. I had thought it did, but by the end of last week's argument, I was no longer sure.