Sean Higgins reports for the Washington Examiner on the dicey proposition facing employers who want to comply with federal immigration law.

A new federal guidance for employers illustrates the Catch-22 situation that immigration law creates for them: Businesses cannot employ anybody who is not legally residing in the U.S., but trying to determine if any of their employees are not legal residents can result in the business facing a federal discrimination lawsuit.

In other words, it can be illegal for an employer to try to find out if it is complying with the law.

The Justice Department and Immigrations and Customs Enforcement jointly issued a memorandum on Dec. 14 meant to clarify an employer’s responsibilities, although the law itself has been on the books for decades.

“This is the first time Immigration and Customs Enforcement has actually come out with these guidelines in terms of … what an employer should do when they are confronted with information that someone may not be authorized to work,” said Kim Thompson, an immigration lawyer with the management-side firm Fisher and Phillips.

The new guidance says, among other prohibitions, that employers cannot inquire on the basis of a worker’s “citizen status or national origin.” Nor can they request specific documents or act based on tips. They cannot use the government’s E-Verify system after the worker is hired. Even if they do find faked documentation, they cannot necessarily act on it.

“The message is, ‘Think before you audit — Is this really something you want to undertake?’ Particularly in-house, because it is fraught with landmines,” said Beth Milito, senior executive counsel for the National Federation of Independent Business.

The problem arises from the fact that the Immigration Reform and Control Act specifically prohibits hiring people who aren’t in the country legally.

However, the government has long held that employers must also abide by various federal civil rights and worker protection laws regardless of their workers’ immigration status. In general, the employer must bend over backward to resolve any questions over legal status without firing the employee.