State Attorney General Letitia James announced a lawsuit Tuesday against the Trump Administration over its new "public charge" rule denying green cards to legal immigrants who have used or who may need subsidized housing, Medicaid or food stamps. James said this broader definition of who's at risk of being a public charge is illegal because it violates the due process clause of the Constitution's prohibition on discrimination.

"This new rule would effectively exclude from entry into the United States millions of black and brown low income immigrants, many of whom are on their way to build stable and more prosperous lives," she said at a press conference at Foley Square joined by unions, elected officials and immigrant rights groups.

Many in attendance said legal immigrants have a long history of arriving poor and then thriving, even if they temporarily need help from the government.

"No one here can guarantee their future will be so bright they will not have a bad day," said Congressman Adriano Espaillat, whose district includes Upper Manhattan and the Northwest Bronx.

The Trump administration has said it’s trying to protect taxpayers, by preventing immigrants from becoming permanent residents if they are not self-sufficient and may need government assistance. The rule would go into effect on October 15th. It would affect legal immigrants already in the country, although very few are even eligible for public assistance, as well as those seeking to move here. Age, health and income would all be considered, as well.

New York's lawsuit notes that the term "public charge" has previously been defined only in very narrow circumstances where immigrants are "unwilling or unable to work and have no other source of support," and are therefore likely to be primarily dependent on the government in the long term. But the Trump administration's new definition would "radically realign national immigration policy in a manner both proscribed by Congress and unauthorized by law."

It also cited the administration's "explicit animus against immigrants of color," noting that those from places the president has previously described as "shithole countries" will be excluded to the benefit of white, wealthy Europeans.

New York would suffer, according to the claim, because legal immigrants will withdraw from programs Congress designed to "promote stability and upward mobility" out of fear they will not be allowed to obtain green cards. It said this will lead to an increase in homelessness, food insecurity and untreated medical issues—forcing state and local governments to expand their own resources. James cited an estimate that New York could lose over $1 billion in federal funds if people forgo assistance to which they are legally entitled.

"We already know of people who are avoiding care, even though this rule has not gone into effect, because there's so much misinformation, so much fear, the rule itself is so complicated," said Mitchell Katz, Chief Executive Officer of New York City's Health and Hospitals, noting that the situation is extra confusing in families where one parent has a green card and the other does not and their children are U.S. citizens.

Prior to the new rule’s announcement last week, New York City had already calculated that 75,000 residents could be forced to choose between accessing benefits to which they are legally entitled and “possible future adverse immigration consequences.” The city has also seen a steeper decline in food stamps among non-citizens than citizens.

New York state's lawsuit is joined by New York City as well as Connecticut and Vermont. California has also sued to block the new public charge rule from going into effect on October 15th.

New York City’s Immigrant Affairs office encourages immigrants to call the City-funded ActionNYC hotline at 800-354-0365 and say "public charge" from 9:00 am to 6:00 pm, Monday to Friday, for answers to any questions about the public charge rule.

Beth Fertig is a senior reporter covering courts and legal affairs at WNYC. You can follow her on Twitter at @bethfertig.