The feds are supposed to enforce our nation's immigration laws. But that just got harder, thanks to a ruling by a federal judge.

In response to a lawsuit filed by the AFL-CIO, the ACLU and the National Immigration Law Center, Judge Maxine Chesney issued a temporary restraining order blocking the Department of Homeland Security and the Social Security Administration from mailing new "no-match" notices to employers.

These notices would have informed employers when information provided by employees (name, Social Security number, etc.) does not match SSA records. The mailings also would have explained what the employers are required to do when they receive a no-match.

DHS/SSA considers these notices to be an immigration enforcement tool. In 2005, SSA mailed out about 10 million no-match notices. By some estimates, up to 90 percent of the workers involved aren't legally entitled to be in the United States.

These critical notices help our country crack down on illegal employees if we're going to re-establish the integrity of American immigration laws. The obstacles thrown in the path of the administration's most recent effort offer an object lesson for Congress in what needs to be done to enforce U.S. laws and get America's employers the workers they require to keep the economy free and prosperous.

By and large the new notices blocked by the court appear to do little more than consolidate existing DHS/SSA policies. They don't create any new requirements. Rather, they provide guidance to responsible employers on how to take reasonable measures to do the right thing - respecting the rights of individual employees while providing a credible means to avoid unintentionally hiring illegal aliens.

DHS also argues that the notices are practical. They allow sufficient time, up to 90 days, for legitimate employees to correct their information without being unduly inconvenienced. The number of individuals required to reconcile no-match data should be manageable for most employers. And employers that responsibly follow the new procedures are granted a "safe harbor," a guarantee from DHS that they won't be prosecuted for willfully violating workplace laws.

Without question, blocking the no-match notices will in some respects put American employees at greater risk. They would have helped legitimate workers correct their data, ensuring they and their families aren't wrongly denied benefits and offering them protection against identity theft.

The lawsuit also demonstrates what would have happened if a comprehensive immigration and border-security bill that put "amnesty first" had passed. Enforcement measures would have been "litigated to death," while amnesty would have allowed millions to scuff U.S. laws, undermining any notion the government could or would enforce immigration laws in the future.

While the administration should receive praise for trying to do the right thing, even proponents of enforcement acknowledge that merely issuing clear no-match guidance isn't the optimum enforcement tool.

It would be better for SSA to routinely share no-match data directly with DHS. This can be done in a manner that protects individual employees' sensitive information and civil liberties. At the same time, with this data DHS could more efficiently prevent employers from encouraging illegal immigration.

There is a dispute, even within the administration, over whether DHS is allowed to automatically receive no-match data under existing law. The administration should ask the Department of Justice to issue a ruling on this matter. Meanwhile, Congress should pass legislation that specifically authorizes SSA/DHS information sharing. This will prove our lawmakers are serious about seeing laws enforced.

Moreover, Congress should provide employers additional protection from frivolous suits by unions and others claiming to represent employees. Employers should receive immunity from liability (except perhaps job reinstatement) for good-faith actions taken to comply with the law.

Meanwhile, DHS should continue to work to answer employers with legitimate questions about how to comply with long-ignored laws. For example, many employers would benefit from learning about the option to participate in E-Verify, an online tool for checking Social Security numbers and correcting no-match errors.

There's plenty of work to do. Our courts need to allow Washington to do its job of protecting the homeland and cracking down on illegal aliens. Meanwhile, lawmakers need to show they're serious about solving this problem, for good.

James Jay Carafano is Senior Research Fellow on National Security Issues at The Heritage Foundation (heritage.org).