Debate over President Obama's executive action on immigration, which could bring up to 5.2 million immigrants out of the shadows, raged on this week in the courts and the halls of Congress.

With Department of Homeland Security funding on the line, Senate leaders have been grappling over a funding bill that would gut the president's deferred action programs for unauthorized immigrants. Meanwhile, a group of 33 mayors filed an amicus brief on Jan. 26 supporting the president's action as part of a federal lawsuit brought by a 26-state coalition trying to block the policy.

Support for and against deportation relief for unauthorized immigrants has split largely down geographic and partisan lines, leading some to remark on the discrepancy between the size of some states' unauthorized immigrant populations and their opposition to the president's action.

"In a telling comparison, the cities backing Obama in the federal case actually house a larger population of undocumented immigrants than the states opposing him," writes Ronald Brownstein in National Journal.

"More broadly," Brownstein continues, "the states opposing Obama also tend to be those more sheltered from the broader wave of immigration that has washed over America since the 1960s."

This is especially the case in the South*, where many state and congressional leaders have opposed the president's action. All but two Southern states are suing the president over the policy. But in the U.S. Senate, the four lone Southern Democrats are opposing the funding bill that would undermine the President's deferred action programs, including the 2012 Deferred Action for Childhood Arrivals program. (Senate Majority Leader Mitch McConnell of Kentucky also voted against the bill but as a procedural step to bring it back up for a vote.)

With the exception of Texas and Florida, Southern states have historically been bypassed by broader U.S. immigration trends and consequently have had small Latino and Asian immigrant populations. This began to change in the 1990s as immigration rates shot up across the region, particularly in states like Georgia, North Carolina and Tennessee that have emerged as new immigrant destinations.

In North Carolina, for example, the foreign-born population grew 274 percent between 1990 and 2000 and by another 74 percent between 2000 and 2010. But even in states like Alabama, which isn't known as a hub for the foreign-born, the immigrant population grew by 102 percent between 1990 and 2000 and 85 percent in the past decade.

The recent trends in immigration are affecting the current national debates. While the immigrant population is relatively smaller in the South, these changes are rapidly re-shaping communities in the region, fueling new opportunities for growth as well as anxiety and backlash over the changing complexion of towns and cities that is evident in the response from many Southern leaders.

The trends also affect the proportion of unauthorized immigrants who are eligible for the president's deferred action plans.

The Migration Policy Institute notes that states with more established unauthorized immigrant populations have higher rates of eligibility for deferred action as more immigrants in those states meet program eligibility requirements like having a child who is a citizen or legal permanent resident and living in the U.S. for at least five years. But in Southern states including Alabama, Louisiana, Mississippi, Kentucky and Virginia, over 30 percent of the unauthorized population does not meet the five-year residency requirement. In Texas, by comparison, only 21 percent of unauthorized immigrants have been in the country for less than five years.

While the South's state and congressional leaders largely oppose the president's action, a handful of local leaders from the region are expressing support for the immigration measures.

Three Southern mayors -- Kasim Reed of Atlanta, Anise Parker of Houston, and Steve Benjamin of Columbia, South Carolina, all Democrats who have been vocal pro-immigrant supporters -- are among the mayors backing the president in the lawsuit against executive action. Houston and Atlanta have particularly large relief-eligible immigrant populations. Harris County, Texas, home to Houston, has the second largest relief-eligible population by county in the country with 172,000 immigrants potentially eligible for deferred action. The Atlanta metro area including Fulton, Gwinnett, DeKalb and Cobb counties accounts for 68,000, about 40 percent of Georgia's total relief-eligible population.

Other sizable unauthorized immigrant populations are also found in cities including Charlotte and Raleigh in North Carolina and Nashville, Tennessee. While the mayors of these cities didn't sign on to the amicus brief, Southern metros have generally struck a more welcoming tone than state leaders. As growing immigrant communities integrate into cities, the stage could be set for potential clashes between states and localities over immigration issues.

* Facing South counts among the Southern states Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Texas, Virginia and West Virginia.