Treasury Secretary Steven Mnuchin has once again refused to release President Donald Trump‘s tax returns to House Democrats. He has argued that their stated legislative purposes hides their real intent which is to expose the president’s personal and business financial records to the public. This is the second time Mnuchin has refused a congressional order to turn over Trump’s tax records.

House Ways and Means Committee Chairman Richard Neal (D-Mass.) met with Mnuchin to request tax returns, but Mnuchin only responded by saying he would give a final response by May 6, when the Justice Department is expected to have completed its review of the request.

In an open letter on Tuesday, Mnuchin request raised “serious constitutional questions” and that his department continued to consult with the Justice Department.

In the letter, Mnuchin says Neal’s request is just “the culmination of a long-running, well-documented effort to expose the president’s tax returns for the sake of exposure.”

The Trump Administration claims that asking for the returns is an illegal violation of Trump’s privacy. But Democrats claim the law is on their side. House leaders are employing a portion of the tax code that grants tax-writing congressional committees the power to request tax information on any filer. They say they need to know if Trump’s business interests are influencing his decisions as president.

Democrats want to see is if Trump benefited from his 2017 tax overhaul, to see if he has ties to foreign businesses and whether he cheated on his taxes.

But Mnuchin isn’t buying it. He noted that House Democrats believe they “need simply recite a legislative purpose, after which the department must ignore all evidence in the public record, however overwhelming, that the asserted purpose is pretext for a constitutionally suspect one.”

One of Trump’s attorneys William Consovoy has argued that Neal’s request doesn’t have a legitimate purpose and flouts fundamental constitutional constraints.