With one day left before Arizona's immigration law goes into effect, passions are running high as those for and against the measure prepare for large scale protests.

"There are various types of non-violent direct action that have no risk at all as far as legal arrests. But when you're talking about civil disobedience, that's when you understand there is a risk," explained Isaac Martin, a local activist holding a training class for people who want to protest the immigration law.

Phoenix Police Sgt. Steve Martos said they're ready for those risks.

"For the most part, 90, 95 percent of people are coming here strictly to voice their opinion," Sgt. Martos said. "There may be a few that want to do something above and beyond that and again we're prepared for that."

The U.S. Justice Department is suing to stop the law from taking effect. But Arizona Gov. Jan Brewer has asked a federal judge to dismiss the challenge.

Unless the judge rules otherwise, the new measure will go into effect Thursday. The new law will make it a state crime to be in the country illegally.

"What it will be is a deterrent," explained Jordan Sekulow, director of operations for the American Center for Law and Justice. "What it tells illegal immigrants is that if you are coming to Arizona illegally, and we find out, we have a system in place now to stop it and do something about it."

But critics argue that the law amounts to racial profiling.

"The biggest thing is how it legalizes racial profiling and actually mandates for police to pull people over, stop people on the street if they have even a reasonable suspicion that they're immigrants - which there is no way to actually do that except by the color of someone's skin," said one Arizona resident who opposes the law.

Protests have taken place in cities across the country ever since the law was signed in April. Many Hispanics, both legal and illegal, say the measure has made it unpleasant for them to stay, so they are leaving.

"They're in fear," Arizona grocery store owner Rosaria Peralta said. "They want to either go back to other states or they're just not buying at all. They're buying the minimum because they just want to save their money so they can move maybe to another state."

For now, all eyes are on the federal court in Phoenix as a judge decides the fate of Arizona's immigration law.