(CNN) — Florida's ban on sanctuary cities just went into effect.
What will that mean in a state that demographers estimate is home to nearly 800,000 undocumented immigrants?
That depends on who you ask. Florida Gov. Ron DeSantis, who made passing the ban a campaign promise, argues it will make communities safer by requiring police to help ICE.
The city of South Miami and several immigrant-rights groups, who filed a lawsuit challenging the ban, say it endangers public safety by fueling fear of law enforcement in immigrant communities.
Florida's measure forbids law enforcement agencies and local governments from adopting such so-called sanctuary policies that limit cooperation with federal immigration authorities.
But there's one key detail to keep in mind: No Florida municipalities had designated themselves as sanctuary cities before SB 168 passed. So the actual effect of the ban, beyond political symbolism, remains to be seen.
The measure requires local jurisdictions to hold undocumented immigrants who've been jailed for up to two additional days to give ICE officers a chance to pick them up and says local law enforcement agencies must use their "best efforts to support the enforcement of federal immigration law."
On Monday a federal judge blocked part of the law that said local police officers could transport immigration detainees across state lines if ICE requests it, but allowed the rest of the law to go into effect.
Many of the largest cities in the United States have sanctuary policies in place. More than 30 bills related to sanctuary policies -- both for and against them -- are pending across the country, according to the National Conference of State Legislatures.