Twenty states have filed a lawsuit seeking to block a Trump administration rule that makes it more difficult for immigrants to obtain visas and green cards. The lawsuit, filed Tuesday, challenges the Department of Homeland Security's "public charge" rule, which expands the criteria used to determine if an immigrant is likely to become a "public charge" and thus ineligible for legal status.

The rule, finalized in August and set to take effect October 24, allows immigration officials to consider a wider range of public benefits, such as food stamps, housing assistance, and Medicaid, when assessing an immigrant's application. Previously, only cash assistance programs were primarily considered.

Attorneys general from states including California, New York, and Illinois, among others, argue the rule would harm their economies and public health systems by deterring immigrants from using essential services. They contend the rule is arbitrary, capricious, and contrary to federal law, and that it will negatively impact diversity and the workforce within their states.

Supporters of the rule, including the Department of Homeland Security, argue it is necessary to ensure immigrants coming to the U.S. are self-sufficient and do not place an undue burden on taxpayers. The administration stated the rule upholds the principle that immigrants should be able to support themselves financially.

The lawsuit claims the rule will lead to a chilling effect, causing immigrants to forgo necessary benefits, potentially leading to negative health outcomes and increased strain on state and local resources. It also asserts that the rule is inconsistent with the Immigration and Nationality Act, which requires consideration of an applicant's likelihood of becoming a public charge.

This legal challenge represents a significant hurdle for the Trump administration's efforts to reshape immigration policy. Similar challenges have been mounted against other administration policies, with courts often scrutinizing the legality and impact of new regulations.

The states involved in the lawsuit include California, Colorado, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nevada, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont, Virginia, and Washington D.C.

The plaintiffs are seeking an injunction to prevent the rule from taking effect, arguing that the potential harm to their states is immediate and irreparable. The case is expected to be closely watched as it could significantly alter the landscape of legal immigration in the United States.