In a rare show of bipartisan resolve, on June 27, 2013, the Senate passed a bill intended to overhaul U.S. immigration laws. Included in the bill — but unlikely to make it past the House of Representatives — was a 13-year path to citizenship for the 11 million unauthorized immigrants in the United States, as well as increased border-security regulations. While the Speaker of the House, John Boehner, has indicated that he may back comprehensive immigration reform, the process is likely to be a long and fraught one, leaving federal, state and local officials to enforce existing regulations in the meantime.

As with all regulations, immigration laws may or may not have the desired impact. It’s easy for elected and unelected figures to say that authorities should “get tough” on undocumented immigrants, but how enforcement would play out on the local level is harder to control. A 2012 study in the Journal of Public Administration Research looked at enforcement in 237 U.S. cities from 2007 to 2008, and found that police officers checked immigration status in 87% of arrests for violent crimes, but only 21% of traffic violations. Moreover, cities with high shares of immigrants tended to experience less aggressive enforcement. At the same time, a 2011 Migration Policy study found that only half of those detained under Section 287(g) of the U.S. Immigration and Nationality Act had committed serious crimes.

The Immigration and Nationality Act, which enables local law enforcement agents to detain and arrest those suspected of violating immigration laws, was introduced in 1996, but little applied until the events of Sept. 11, 2001. By 2011, 68 local law enforcement agencies in 23 states had 287(g) agreements. In 2012, however, President Obama, calling the program inefficient and unproductive, suspended its funding and the Department of Homeland Security has not signed any new contracts since. At the same time, a number of states have introduced copycat legislation to Arizona’s SB 1070, which allows police to check the immigration status of those they detain.

The interplay of Federal, state and local laws, their enforcement and economic factors all affect the number of detentions and how immigrants react. For example, a 2012 report from the U.S. Bureau of Justice Statistics found that apprehensions for immigration violations dropped to 516,992 in 2010, even as the share of immigration offenders admitted to the Federal Bureau of Prisons increased from 19% of all offenders admitted in 2000 to 29% in 2010.

A 2013 study, written by Tara Watson, a visiting scholar at the New England Public Policy Center of the Federal Reserve Bank of Boston, focuses on the effects, intended and unintended, of the 287(g) program. Titled “Enforcement and Immigrant Location Choice,” the study used data from the American Community Survey to examine responses to local enforcement agreements with federal authorities.

The study’s key findings include:

• The largest effects of 287(g) enforcement were found among college-educated noncitizens, most of whom relocate to other local areas or regions within the United States rather than out of the country. This population segment accounts for a 2.9-percentage-point increase in migration. This suggests that enforcement programs “may be missing their intended targets,” the author writes.
• The enforcement policies themselves do not seem to cause migration to other cities, regions and states. Instead, immigrants appear to be “eager to leave areas in which hostility to the foreign-born is evident at the street level.”
• The controversial local “task force” model of 287(g) enforcement, which emphasizes street enforcement, nearly doubles the propensity for the foreign-born to relocate within the United States. Such enforcement leads to a 45% to 63% increase in out-of-state migration, which is 1.7 to 2.3 percentage points above that for the native-born population.
• While task-force agreements can have a large impact, they haven’t been implemented widely across the United States: At the peak of agreements, only 3.5% of immigrants in the U.S. were exposed. Despite this, the law may have caused inefficient distribution of the labor supply as immigrants, in the absence of such immigration laws, naturally gravitate to areas where labor is needed.
• The degree of enforcement or enforcement model does not deter people from coming into states with 287(g) agreements from elsewhere in the country.
• The study did reveal a relationship between enforcement and out-migration from the United States, but it was driven entirely by the inclusion of Maricopa County, Arizona. The jurisdiction is known for “intensive and often controversial enforcement tactics” and is only a short distance from the Mexican border, making out-migration a more practical response to aggressive enforcement. “Excluding Maricopa, there is no evidence that 287(g) enforcement drives out-migration from the United States.”

“Even though the task-force model itself has been eliminated, widespread implementation of [such] enforcement regimes … could drive redistribution of immigrants within the United States,” with significant economic outcomes. Watson concludes, “As the nation debates immigration policy, understanding the impacts of enforcement on immigrants’ behavior is critically important.”

A related 2010 study from Baylor University and Texas Wesleyan School of Law, “The Economic Impact of Local Immigration Regulation,” investigates the economic impact of restrictive immigration laws. It found that in places where local anti-immigration laws were enacted, employment fell by 1% to 2%. On average, 337 to 675 jobs were lost in jurisdictions that implemented such laws. This translates to 40 to 80 jobs lost in the median county.

Keywords: crime