The Massachusetts Democrats have stated that defying his request – which the IRS is expected to do – would be interpreted as non-conformity and lead to an escalation in the distance between the administration and the house-democrats over the president's financial register.
"It is not the right function of the IRS, Treasury or Justice to ask or others guess the justification of the committee or its reasonable determination regarding its need for the requested returns and return information," Neal wrote to the IRS Commissioner Charles Rettig. "Please know that if you fail you will follow your failure as a rejection of my request."
But in a new hearing, Rettig said that Mnuchin is his boss and Mnuchin has made clear that he has no plans to hand over documents at any time soon.
Mnuchin told reporters earlier this month that it would be "premature" to decide how long the agency's review with the Justice Department could take into account the legal issues. He also called Tuesday's deadline "arbitrary".
President's personal lawyer William Consovoy has sent two letters to the Treasury Department, which urged them not to abstain, claiming that Neal reached its Congress authority under the law.
Trump has broken decades of the presidency's precedent with his refusal to release his proceeds, first as a candidate and after taking office. He has also kept his efforts in his real estate business, now overseen by his adult sons Don Jr. and Eric Trump, and opens up challenges that he violates the constitutional ban on presidents taking gifts or money from foreign governments or US government entities.
Democrats refer to an obscure statute
Democrats are firm in their belief that Neal is empowered under IRS 61
The statute has been used by Congress before and was used in a high-profile case when Congress examined whether the IRS was discriminated against conservative groups who applied for non-profit status. Request for information using 6103 is made regularly for research purposes by JCT.
Neal claims he needs Trump's taxes to be able to monitor the IRS presidential audit program, both to understand how the IRS uses the program and see if the program needs to be codified in law.
Trump's lawyer claims that Neal only uses the Presidential Audit Program as a phenomenon to spoil the president and release Trump's private information to the public.
"Congress has no constitutional authority to act as a junior varsity IRS, conduct individual investigations or fly up the agency's calculations," Consovoy wrote to the treasury last week.
A long legal battle is expected
The administration's denial of the request is expected to kick a long legal battle against the 6103 Charter, which has never been reviewed by the courts before. The fight will also be a rare example of the congress that suits the executive department for information, and can continue for months or even years.
In 2012, the House voted to hold when lawyer Eric Holder in contempt of Congress and the House Oversight Committee sued the Obama administration for information related to the program, but it was not until 2014 that the Court ruled the administration had to submit additional documents. Even so, the villain continues the documents today.
CNN's Donna Borak contributed to this report.