At least 12 states have responded with a wave of fury and legal action this week after the Trump administration announced it would add a question to the 2020 census asking respondents whether they are U.S. citizens.

New York Attorney General Eric Schneiderman said he would lead a multistate coalition to block the decision the Commerce Department announced on Monday. The addition of a citizenship question is highly controversial, and civil rights groups have long claimed it could jeopardize the accuracy of the census.

“A fair and accurate count of all people in America is one of the federal government’s most solemn constitutional obligations,” Schneiderman said in a statement released Tuesday. “The Trump Administration’s reckless decision to suddenly abandon nearly 70 years of practice by demanding to know the citizenship status of each resident counted cuts to the heart of this sacred obligation – and will create an environment of fear and distrust in immigrant communities that would make impossible both an accurate Census and the fair distribution of federal tax dollars.”

The states of Connecticut, Delaware, Illinois, Massachusetts, New Jersey, New Mexico, Oregon, Pennsylvania, Rhode Island and Washington quickly said they would join the lawsuit, with state officials condemning the citizenship question as an “arbitrary” one that would “only do harm.”