This legislation significantly amends federal law to clarify and strengthen requirements for information sharing between state and local governments and federal immigration authorities. It explicitly prohibits any state or political subdivision from enacting or enforcing policies that materially restrict the sharing of lawfully obtained information, including immigration status, custody details, and release dates, with the Department of Homeland Security (DHS) or other government entities. Such restrictions include those that prohibit, delay, condition, or penalize officials for sharing information or require advance approval that hinders timely transmission. The bill mandates that state and local jurisdictions provide DHS with timely notification of an individual's release from criminal custody, requiring up to 48 hours advance notice for scheduled releases and immediate notification with a potential 48-hour custody hold for unscheduled releases. It also grants state and local law enforcement officers immunity from personal liability when performing duties related to immigration enforcement, such as detaining or transferring individuals to federal custody. To ensure compliance, the Attorney General is authorized to bring civil actions for declaratory or injunctive relief against non-compliant jurisdictions. States or political subdivisions found by a court to be in knowing violation of these provisions may also be deemed ineligible for certain law enforcement grants administered by the Department of Justice.