The perceived legitimacy of U.S. law effects immigrants' decision to cross the U.S.-Mexico border illegally more than fear of arrest and punishment, according to new research published in the August issue of American Sociological Review.

Unsurprisingly, the study found that people entered the United States illegally in search of better jobs and better economic opportunities. Those who believed it was very dangerous to cross the border illegally were less likely to do so. Fear of arrested and punishment, however, appeared to have no effect on immigrants' decision to migrate illegally.

"Economic cost-benefit calculations matter, but they don’t offer a complete account of decisions to migrate illegally," study author Emily Ryo of Stanford University told Raw Story. "In particular, perceptions about the probability of arrest and the severity of sanctions are not significant determinants of those decisions."

The study found immigrants' decision to migrate illegally was influenced by the belief that disobeying the law is sometimes justified or that it was okay to migrate illegally to make more money. Immigrants were also influenced by the belief that Mexicans had a right to be in the United States and the perception that family and friends have tried to migrate illegally.

The above-mentioned beliefs were associated with the perception that the U.S. immigration service mistreated Mexicans. Those who believed the U.S. immigration service treated lighter-skinned immigrants better than darker-skinned immigrants were nearly three times more likely to believe the U.S. government had no right to limit immigration.

"People’s personal values and social norms are important determinants of their intentions to migrate illegally, even controlling for relevant demographic and economic factors," Ryo explained. "These law-related attitudes, value orientations, and shared beliefs about what’s right and appropriate allow people to violate U.S. immigration laws by enabling them to see this particular law violation as a moral and legitimate option in face of their economic need. This finding is important because economic incentives alone typically don’t induce otherwise law-abiding people to violate the law (something that we often seem to forget when it comes to unauthorized migrants)."

The study relied on data from the 2007 and 2008 Mexican Migration Project (MMP) and Becoming Illegal Survey (BIS), which surveyed more than 1,600 men.

The new study comes as Congress debates comprehensive immigration reform legislation, which would provide undocumented immigrants with a 13-year path to citizenship while beefing up security at the U.S.-Mexico border.

The study suggests that cracking down on illegal immigration could increase the feeling that the U.S. lacks legitimacy and inadvertently make the situation worse. Arizona's controversial immigration law, for instance, created a widespread perception of racial bias, which might have made Mexican immigrants less likely to comply with the law.

"Continuing efforts by the U.S. government to selectively target and marginalize unauthorized Mexican migrants might thus have the unintended consequence of producing lesser, rather than greater, voluntary deference to U.S. immigration law, as increasing numbers of Mexicans come to question the legitimacy of U.S. legal authority," Ryo wrote in her study.

"What I find is that people’s perceptions about the legitimacy of U.S. authority is a significant determinant of their intentions to migrate illegally," she told Raw Story.

"Moreover, my findings show that people’s perceptions about procedural justice and fairness are significantly related to their legitimacy perceptions," Ryo continued. "Now, I should note that my study cross-sectional study, so it can’t directly address questions of causality. However, I would not be surprised if enforcement measures that strengthen prospective migrants’ perceptions of bias, racism, arbitrariness, and hypocrisy generate greater noncompliance, all else being equal, precisely by making those laws seem unworthy of obedience."