CNN — A new law that makes entering Texas illegally a state crime is sowing confusion and uncertainty among undocumented migrants and mixed status families along the US-Mexico border, according to immigration advocates. Many of those advocates tell CNN they fear a wave of racial profiling as well as detentions and attempted deportations by state authorities when the law is expected to take effect in March. “There are a lot of unknowns about how this law will be implemented,” Houston immigration attorney Roberto Quijano said a recent town hall meeting about the law. Republican Gov. Greg Abbott signed the measure, Senate Bill 4 , into law on Monday, granting local law enforcement the power to arrest migrants and judges the ability to issue orders to remove them to Mexico, in a state where Latinos represent 40% of the population. “We have a lot of concerns about racial profiling and racism,” Ramona Casas, a community organizer with the nonprofit Arise Adelante, said this week at a protest against SB4. “These laws open the door for that. They threaten families.” Casas said she believes Latinos in Texas will be forced to carry their passports and IDs at all times in order to avoid being detained on suspicion of being undocumented. White House slams new Texas immigration law as feds mull possible challenge For many opponents the new law harkens to a similar 2010 “Show me your papers” law in Arizona – which was largely struck down by the US Supreme Court two years later. The high court concluded in 2012 that the federal government had the power to block the law but let stand a controversial provision allowing police to check a person’s immigration status while enforcing other laws if “reasonable suspicion” existed that the person is in the United States […]