Democrats did not hear what they wanted to hear in the Mueller report. Now their new battle centers on President Donald Trump’s tax returns.

House Ways and Means Committee Chairman Richard Neal, D-Mass., filed a lawsuit Tuesday against Treasury Secretary Steven Mnuchin and IRS Commissioner Charles Rettig to obtain years of the president’s tax returns.

The committee requested Trump’s tax returns in March, citing section 6103 of the Internal Revenue Code, which states the Treasury Department “shall furnish” 10 years of tax returns to one of three congressional committees: the House Ways and Means Committee, the Senate Finance Committee, or the Joint Committee on Taxation.

Citing guidance from the Department of Justice, Mnuchin rejected the subpoena in May, arguing the request had not “legitimate legislative purpose.”

In the lawsuit filed Tuesday, Democrats are demanding the court to enforce the subpoena requesting the returns and maintain they do not need to justify their request under that statute.

 They argue in court filings that the committee has the right to access Trump’s private tax information under that section of the federal tax code which states the Treasury “shall furnish” an individual’s returns if a formal written request is made.

“In refusing to comply with the statute, Defendants have mounted an extraordinary attack on the authority of Congress to obtain information needed to conduct oversight of Treasury, the IRS, and the tax laws on behalf of the American people who participate in the Nation’s voluntary tax system,” the complaint says.

 “The Committee has been unable to evaluate President Trump’s claims about the audit program or investigate its other concerns because the President has declined to follow the practice of every elected President since Richard Nixon of voluntarily disclosing their tax returns,” the court filing states.

“Without reviewing the requested return materials, the committee cannot ensure that the IRS’s audit process is functioning fairly and effectively, understand how provisions of the tax code are implicated by President Trump’s returns, or exercise its legislative judgment to determine whether changes to the code may be warranted.”

The New York State Senate is also are waging a battle demanding the president release his tax returns.

The New York Senate passed legislation in May authorizing the release of tax returns, circumventing the confidentiality of the returns. New York Senate bill, S2271, mandates the disclosure of tax returns by statewide elected officials including the president of the United States.

New York’s Democrat Governor Andrew Cuomo has indicated that he would sign the bill.

Trump’s 2005 tax return was recently leaked, but Democrats’ main goal is to publicly disclose the president’s tax returns from the 80s. Specifically, they are seeking returns involved in a 1984 trial, where Trump was accused of committing fraud.

Trump claimed zero revenue for his businesses and $600,000 in deductions with no documentation — plus, his tax preparer admitted to signing the tax return, but refused to admit he prepared the documents.  However, the trial is 33 years old, and the statute of limitations for IRS actions on income tax is a mere three years.