Backlash to the law has been fierce—from entertainers, businesses, and most recently the Obama administration. In a letter on May 4, Deputy Assistant Attorney General Vanita Gupta informed McCrory that the Department of Justice had determined that HB2 violated Titles VII and IX of the Civil Rights Act. Gupta said that the state should respond by Monday agreeing not to enforce the law, or it would risk having the federal government shut off the spigot of money that goes to states for education.

Republican leaders in the Old North State did not take the letter kindly. House Speaker Tim Moore said that state would not comply. McCrory, also a Republican, was slower to respond—he complained about the letter but did not announce his plans. Over the weekend, he said on Fox News Sunday that he had requested more time to respond to the federal government. McCrory said DOJ had offered him a one-week extension if he was willing to admit the law was discriminatory, which he was not. “It’s the federal government being a bully, making law,” McCrory said Sunday. The Justice Department did not immediately return a request for comment about the condition. According to The News and Observer, a Justice spokeswoman said in a statement Sunday, “On Friday, the department received requests from multiple parties for an extension of the deadline in our May 6 letters. The discussions regarding those requests are ongoing.”

McCrory’s lawsuit on Monday asks federal courts to clarify on a couple key areas of the law. The Justice Department notes that Title VII of the law prohibits employment discrimination on the basis of gender, and says that courts have interpreted that to include gender identity of transgender people. In the suit, McCrory asks federal courts to issue a declaratory judgment saying that the state is not in violation of Title VII or of the Violence Against Woman Act.

“North Carolina does not treat transgender employees differently from nontransgender employees,” the complaint argues (via WRAL). “All state employees are required to use the bathroom and changing facilities assigned to persons of their same biological sex, regardless of gender identity, or transgendered status.”

The Justice Department did also not have an immediate response to the suit.

The mechanism of the federal government's threat is somewhat complicated. While the law might violate the Civil Rights Act, such a ruling would have to come from a federal court, not the Justice Department. But Washington provides billions of dollars to the states for education. Interpretation of Title IX generally follows Title VII, so if the federal government decides that a law like HB2 violates Title IX, it can threaten to cut off money to the states.

That’s a powerful threat—North Carolina receives billions in essential funding. McCrory’s lawsuit hopes to get courts to rule that withdrawing that money is improper. The request should buy the governor time, but it’s unclear how promising the court landscape will be. In April, a panel of judges on the Fourth Circuit Court of Appeals ruled that the Department of Education could interpret Title IX to include transgender people, a decision that the Department of Justice cited in its letter to McCrory.