Maryland Attorney General Brian E. Frosh (D) announced Thursday that he will join several high-tax states planning to challenge the new federal tax law as illegal because it would "jack up" the amount many residents owe.
The other states in the lawsuit would be Connecticut, New Jersey and New York, whose governors have formed a coalition to sue over the tax plan.
Maryland Gov. Larry Hogan (R) has not asked Frosh to join the suit, but the state legislature last year granted the attorney general broad authority to take legal action against the federal government after the election of President Trump. The measure became law without Hogan's signature.
Frosh has since launched or joined at least 20 lawsuits against the Trump administration, including on issues related to environmental protections, banning some travelers to the United States and alleged conflicts of interest related to Trump's businesses while he is president.
The changes to federal tax law, passed with no Democratic votes in Congress in December, include a $10,000 cap on deductions for state and local taxes.
Frosh said that limit will increase the tax bills of more than 500,000 Marylanders.
"It is an attack on state sovereignty and an attempt to cripple our ability to educate our kids, protect the Chesapeake Bay, and build the infrastructure that Maryland needs to be competitive in the world economy," he said.