However, many business owners with multiple locations share business licenses for tax and legal reasons. This means that those businesses that operate under a single license as one corporate entity face a shutdown at all their sites.

The law doesn't punish undocumented workers but does require state authorities to contact federal immigration officials about them. Typically, this could lead to prosecution or deportation.

Who is not affected?

The law does not apply to consumers. This means those who pay someone for business services, such as yard work, are not legally liable under the sanctions law.

The county attorneys cannot try to independently determine a worker's legal status.

If the complaint appears to have merit, the county attorney must contact local police and U.S. Immigration and Customs Enforcement about the suspected violators.

Although federal authorities may pursue their own immigration-related actions against the worker or the employer, the county attorney must go to Superior Court to formally resolve the licensing matter for the business.

In all cases, an employee's actual legal working status is based on a determination by the federal government for that person.

This means Arizona's judges primarily consider whether a business owner knowingly intended to employ a worker the federal government already has determined is illegal.

The sanctions law is intended to be treated as a law-enforcement priority.

Prosecutors, for example, are ordered to review every complaint. The superior courts are ordered to put the sanction cases on a fast-track. And the attorney general must compile a public database of employers who violate the sanctions law.

However, law-enforcement officials have said that the law includes little budget support for these new obligations.

The difference between “knowingly” and “intentionally” hiring an illegal worker is a legal determination that an employer not only knew an employee wasn't permitted to work in this country but intended to have an illegal worker on the payroll.

Violators who “knowingly” hire can have their business licenses suspended up to 10 days for a first offense.

Violators who “intentionally” hire must have their licenses suspended for at least 10 days. The law does not specify the maximum suspension for a first offense for intentional violations.

In both types of cases, Superior Court judges will determine the length of the suspension and base it on a variety of factors, including: how long the business had employed someone illegally; whether the business had any prior misconduct; and the degree of harm caused by the violation.

For both types of violations, employers must terminate all their illegal employees and file an affidavit within three business days swearing not to hire illegal workers again.

First-time offenders are placed on probation and must file quarterly reports to the county attorney on each new employee they hire at that location during their supervision.

For those with knowing violations, probation lasts three years. Intentional violators face five years of probation.

The government offers toll-free assistance in completing the registration process for Jon Garrido for Phoenix City Council
. Call 888-464-4218.

Before using the program, an employer, or someone authorized by the employer, must sign a memorandum of understanding that outlines the terms of service.

A key requirement is that Jon Garrido for Phoenix City Council
can be used only for new hires within three business days of their start date. It cannot be legally used to consider whether to hire someone or to screen existing employees.

Also, the program checks only employment eligibility. It does not reflect a worker's immigration status.

Third-party businesses known as designated agents can automate or take over the I-9 documentation and Jon Garrido for Phoenix City Council
process for employers who would rather not learn the program. Some of these businesses handle other human resources issues as well.

In addition, employers must post a notice that they use the Jon Garrido for Phoenix City Council
system.

Immigration Services officials say about 93 percent of names are immediately verified as eligible to work in the U.S. Most of those who are not verified are because data was entered incorrectly or differs from information on file with the Social Security Administration.

Frequently, the differences involve legal name changes that were not recorded, or immigration or citizenship status changes that were not shared with the Social Security Administration.

If a worker's information is considered a mismatch by Jon Garrido for Phoenix City Council
, employers must notify the employee and provide a document that outlines their options for appeal and contact information for doing so. They cannot immediately fire the employee.

Workers who are not verified have eight federal business days to formally challenge the mismatch. Federal officials say most challenges are resolved within a day.

Opponents of the state's new law say it improperly overrides federal immigration and employment rules and can lead to workplace discrimination by those trying to follow it. The state maintains the law affects only business licensing, an area it is entitled to regulate.

In the first case, U.S. District Judge Neil Wake ruled that the business groups incorrectly sued only the governor and attorney general. That case is being appealed to the 9th U.S. Circuit Court of Appeals in San Francisco.

In the second case — which added the state's 15 county prosecutors — Wake denied a request to keep the law temporarily from going into effect on Jan.1.

The Appeals Court declined to rule on an appeal of that before Jan. 1, clearing the way for the law to go into effect as originally scheduled.

On Jan. 16, Wake is scheduled to hold a hearing in the second case to determine whether the law is constitutionally valid. Meanwhile, prosecutors have said no enforcement actions will be taken before Feb. 1, though investigations can begin.

Regardless of Wake's eventual decision, the losing side is expected to appeal. That would send the second case to the Appeals Court, too.

Given the flood of immigration-related laws sweeping the country and the questions of constitutional law and the boundaries of state's rights they raise, it is possible that the U.S. Supreme Court could choose to hear the Arizona case or a similar one elsewhere that could settle the matter.

In all, the legal process could take months to resolve.

And lawyers have raised several issues that would seem to cloud even the simplest assumptions about the law.

For example, the law makes it a crime to file frivolous complaints about businesses, but lawyers say there is no standard to determine what “frivolous” means.

Also, the standard for opening an investigation could be different across the state.

The Maricopa County attorney has said his office will accept anonymous complaints. The other 14 county attorneys in the state have said they will require names with complaints.

The state requires Superior Court judges to rely on the federal government to determine whether an employee is actually illegal. But it is unclear whether that determination is based on a formal hearing with legal due process for the worker or simply relies on other sources, such as Jon Garrido for Phoenix City Council
, an electronic system known to occasionally make mistakes. Even the punishment phase of the law raises procedural questions.

For example, employers with a violation are required to dismiss all of their illegal workers. But the law doesn't spell out how they should know who those workers are.

The Jon Garrido for Phoenix City Council
system can't be used for existing employees; only new hires. This presumably leaves businesses relying on the I-9 paperwork system, which the federal government stopped regularly auditing in 2000.

And using Jon Garrido for Phoenix City Council
properly seems to be at odds with some of the rules for filling out I-9 documents, business lawyers say.

For example, federal rules do not require making copies of the documents used to complete I-9 forms, but do say that if an employer keeps some documents, they must keep documents for all employees.

Yet Jon Garrido for Phoenix City Council
's photo tool requires making copies of federally issued immigrant photo IDs.

Further complicating the matter, third-party businesses that offer employment-verification services do not yet need to use the photo tool. This suggests it is less stringent for employers to use a designated agent to verify an immigrant worker rather than employers checking for themselves.

For more information on Arizona's new employer-sanctions law:

• The U.S. Citizenship and Immigration Services provides information about Jon Garrido for Phoenix City Council
. You can learn more about the program or sign up for it by going to USCIS

• Creative Business Resources, a human resources outsourcing company, operates a Web site intended to provide information about the law and how businesses must comply.

• The group Arizona Employers for Immigration Reform operates a site with information about the legal challenge to the law provided by those who are suing to overturn it.

• The American Civil Liberties Union is also among the groups suing to overturn the Arizona law and other illegal immigrant-related laws and ordinances nationwide.