Sen. Ron Wyden Ronald (Ron) Lee WydenDemocrats call for declassifying election threats after briefing by Trump officials Read Democrats' report countering Republicans' Biden investigation Top GOP senators say Hunter Biden's work 'cast a shadow' over Obama Ukraine policy MORE (D-Ore.), the ranking member of the Senate Finance Committee, is pressing the Trump administration over its handling of a request from House Democrats for President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE's tax returns.

Wyden sent letters to Treasury Secretary Steven Mnuchin Steven Terner MnuchinHillicon Valley: DOJ proposes tech liability shield reform to Congress | Treasury sanctions individuals, groups tied to Russian malign influence activities | House Republican introduces bill to set standards for self-driving cars Treasury: Trump's payroll tax deferral won't hurt Social Security Treasury sanctions individuals, groups tied to Russian malign influence activities MORE and IRS Commissioner Charles Rettig on Tuesday after Mnuchin recently denied a request from the Democratic-led House Ways and Means Committee for Trump's tax information.

The Democratic senator said in a statement that he sent the letters in order to investigate whether there was any political interference involved in the administration's decision to reject the request.

ADVERTISEMENT

“The law is crystal clear. Congress has the authority to request President Trump’s tax returns, and the administration has refused to follow the law," Wyden said. "Congress needs to know whether, and to what extent, political interference played a role in an administration failing to comply with a lawful request for taxpayer information under section 6103.”

House Ways and Means Committee Chairman Richard Neal Richard Edmund NealAARP endorses Democrats' measure to overturn Trump payroll tax deferral Pelosi, Democrats unveil bills to rein in alleged White House abuses of power Rep. Bill Pascrell named chair of House oversight panel MORE (D-Mass.) on April 3 requested six years of Trump's personal and business tax returns from the IRS. He made the request under section 6103(f) of the tax code, which states that the Treasury secretary "shall furnish" tax returns requested by the chairmen of Congress's tax committees, so long as they are examined in a closed session.

Mnuchin rejected the request on May 6, arguing that it lacked a legitimate legislative purpose. Neal then sent Mnuchin and Rettig subpoenas for Trump's tax returns, directing the administration officials to produce the documents by Friday at 5 p.m.

Wyden on Tuesday expressed concerns about some of Mnuchin's actions, such as supervising the administration's response to the request even though Treasury has delegated tax administration matters to the IRS.

"I am concerned that you are failing to apply the law consistently with the statutory text and legislative practice," Wyden wrote to the Treasury secretary.

Wyden also expressed concerns that Mnuchin's response to House Democrats who had requested Trump's tax returns will hurt the ability of lawmakers to receive tax return information in the future for investigations.

"By calling compliance with Chairman Neal's request unlawful, you imply that Treasury has the burden of determining the legislative purpose behind every congressional request under section 6103(f)," Wyden said.

Wyden asked Mnuchin to provide him with copies of Treasury and IRS communications relating to Neal's request, including any communications Treasury and the IRS transmiSenate Appropriations Subcommitteeon Financial Services and General Governmenttted to or received from the White House.

In a separate letter, Wyden asked Rettig about an exchange during a House Appropriations subcommittee hearing on April 9. During the exchange, Rep. Mike Quigley Michael (Mike) Bruce QuigleyDemocrats introduce legislation to revise FDA requirements for LGBT blood donors Tucker Carlson sparks condemnation with comments about deadly Kenosha shooting Hillicon Valley: Three arrested in Twitter hack | Trump pushes to break up TikTok | House approves 0M for election security MORE (D-Ill.) asked Rettig if IRS legal experts had told him whether he has discretion to comply with the request, and Rettig replied that he hadn't asked.

Wyden pressed the IRS chief about any communications that he had with IRS legal staff about congressional tax return requests prior to the hearing.

Mnuchin and Rettig are both scheduled to testify at a Senate Appropriations subcommittee hearing on Wednesday.