"It's just states trying to deal with what they perceive to be the problem," Mayer said.
Georgia lawmakers, for example, expanded a law passed in 2011 to crack down on illegal immigration. And Arizona and Nebraska officials have refused to grant driver's licenses to young immigrants who are authorized to be in the country under the Obama administration's Deferred Action for Childhood Arrivals directive.
But this is nothing compared with the political climate of recent years where anti-illegal immigration attitudes dominated the national debate.
"This is an interesting evolution," Chishti said.
As recently as few years ago, lawmakers around the nation were passing strict regulations that made immigrants in the U.S. without legal permission the subject of police crackdowns and raids.
"The last few years were so harsh at the state level," said Wendy Feliz, a spokeswoman for the American Immigration Council.
Colorado legislators have been on both sides. In 2006, Democrats and Republicans came together and passed a law requiring local police to notify federal authorities when they arrested someone suspected of living illegally in the U.S. Last month, behind a push from newly elected Democrats, the law was repealed. Activists praised the move as especially symbolic, saying the law was precursor to more high-profile, hard-line regulations in Arizona and Alabama.
Feliz and other immigrants' rights activists are content to support the state-by-state changes, since they can have a more immediate effect on the 11 million people living in the U.S. illegally.
Federal legislation moves at a far slower pace in both approval and implementation. Also, proposals in the nation's capital affect policy, such as how a person becomes a citizen. The state-level changes deal more in daily concerns, such as the cost of education.