The law went into effect over the weekend, after being largely upheld by a federal district judge. Volunteers on an immigrant-rights group’s hot line said that since then they have received more than 1,000 calls from pregnant women afraid to go to the hospital, crime victims afraid to go the police, parents afraid to send their children to school.

School superintendents and principals across the state confirm that attendance of Hispanic children has dropped noticeably since the word went out that school officials are now required to check the immigration status of newly enrolled students and their parents.

That rule is part of the law’s sweeping attempt to curtail the rights and complicate the lives of people without papers, making them unable to enter contracts, find jobs, rent homes or access government services. In other words, to be isolated, unemployable, poor, defenseless and uneducated.

The education crackdown is particularly senseless and unconstitutional. In 1982, the Supreme Court found that all children living in the United States have the right to a public education, whatever their immigration status. The justices’ reasoning was shaped not by compassion but practicality: it does the country no good to perpetuate an uneducated underclass.

Officials in Alabama — some well meaning, others less so — insisted that nothing in the new law is intended to deny children an education. School districts, they noted, are supposed to collect only numbers of children without papers, not names.

“I don’t know where the misinformation’s coming from,” Alabama’s interim state school superintendent, Larry Craven, told NPR. “If you have difficulty understanding the language anyway, then who knows what they’re being told?” With comments like that, it’s not surprising that any of “them” would be frightened.

The Obama administration was right to sue to try to stop the Alabama law. It needs to press ahead with its appeal of the ruling and challenge similar laws in Utah, Georgia, Indiana and South Carolina.

President Obama needs to show stronger leadership in defending core American values in the face of the hostility that has overtaken Alabama and so many other states. He can start by scrapping the Secure Communities program, which encourages local immigration dragnets and reinforces the false notion that most undocumented immigrants pose a threat to this country’s security.

As for Alabama, one has to wonder at such counterproductive cruelty. Do Alabamans want children too frightened to go to school? Or pregnant women too frightened to seek care? Whom could that possibly benefit?