• The Supreme Court heard arguments related to the Trump administration's "public charge" immigration rule.
• An Arizona-led group of red states asked the justices to allow them to defend the rule in federal court, even though the Biden administration had abandoned it.
• Former President Donald Trump's DHS reinterpreted when a non-U.S. citizen is likely to become a public charge and therefore ineligible for permanent residency.

The Supreme Court on Wednesday heard arguments related to the Trump administration's "public charge" rule, an immigration policy that widened the definition of which immigrants can be denied green cards.

An Arizona-led group of red states asked the justices to allow them to defend the rule in federal court, even though the Biden administration had abandoned it. A lower appellate court had denied the states' efforts to intervene to defend the rule.

The justices questioned Arizona Attorney General Mark Brnovich's argument that the Biden administration's maneuvers were "unprecedented."

"The new administration often changes its position in cases. So what's different from this case, in which the administration declines to appeal an adverse ruling?" asked Justice Clarence Thomas, a conservative.

"There's kind of a mismatch here between what you're saying went wrong and what you're saying you want," Justice Elena Kagan, a liberal, said.

The rule in question came in 2019, when then-President Donald Trump's Department of Homeland Security reinterpreted when a non-U.S. citizen is likely to become a public charge and therefore ineligible for permanent residency.

Previous guidance from two decades earlier had defined a public charge as someone "primarily dependent on the government for subsistence," but did not include non-cash benefits, such as food stamps and Medicaid, in making that determination.

The 2019 rule changed the definition of public charge to encompass those and other benefits, potentially making it harder for poor immigrants to gain residency. It had been blocked in lower courts.

Civil rights groups have decried the policy as a "racist wealth test on the immigration system."

Wednesday's oral arguments came less than a week after President Joe Biden put forward a proposal to reverse the Trump-era rule.

Biden as a presidential candidate in 2020 had promised to undo Trump's public charge policy. In March, the Biden administration stopped fighting the legal challenges to the rule that had carried over from the Trump administration.

"The 2019 public charge rule was not in keeping with our nation's values. It penalized those who access health benefits and other government services available to them," Homeland Security Secretary Alejandro Mayorkas said at that time.