Texas and a coalition of states warned Congress this week they will “aggressively defend” against Democrat-priority legislation to impose federal control over states’ election processes.

On Monday, Texas Attorney General Ken Paxton and 22 other Republican attorneys general issued a challenge to U.S. House and Senate leaders, opposing H.R. 4 and promising a legal fight if the bill becomes law.

H.R. 4 establishes the U.S. Department of Justice as a “federal election czar” dictating how states must administer their elections.

The bill would require states to get permission from the federal government before enacting any election reforms—a throwback to “pre-clearance” requirements in the Voting Rights Act of 1965 that were meant to last five years but remained in effect until the U.S. Supreme Court ruled their continued application unconstitutional in 2013.

“The VRA was never intended to require every jurisdiction in the country to submit to this federal control,” the attorneys general wrote:

H.R. 4 permits politically appointed bureaucrats to meddle in state affairs, is unlawful, and violates state sovereignty. This legislation is a misguided, clumsy, and heavy-handed effort to circumvent Supreme Court decisions, state sovereignty, and the will of the people.

“If these provisions are enacted, rest assured that the undersigned will aggressively defend our citizens’ rights to participate in free and fair elections without unconstitutional federal intrusion,” they added.

The Democrat-controlled U.S. House passed H.R. 4 last month. The bill was introduced Tuesday in the evenly split Senate, where Democrats need 60 votes to advance legislation.

H.R. 4 targets state election reform laws like Texas Senate Bill 1. If enacted, it would apply retroactively to state laws passed on or after January 1.

The Republican-run Texas Legislature passed SB 1 during this year’s second special legislative session in August, following months of obstruction by Democrat state lawmakers.

“After fighting long and hard to pass Texas’s SB 1, which helps stop voter fraud and increase public trust in our elections, I refuse to sit back and allow voters in the great state of Texas to be silenced,” Paxton said in a statement. “HR 4 undermines the integrity of our elections, ignores the countless issues with voter fraud, and I am committed to stopping this misguided proposal.”

In March, Paxton and 19 other Republican state attorneys general vowed to fight H.R. 1, congressional Democrats’ top priority legislation. That bill is designed to seize power from state legislatures and impose lax voting procedures preferred by Democrats onto all states.

A similar bill is working its way through the U.S. Senate.

Democrats’ federal election-takeover bills face uphill battles overcoming the Senate’s filibuster rules. If they do become law, they’ll face tough legal challenges from Texas and other states.