The White House will refuse to allow senior adviser Stephen Miller to testify before the House Oversight Committee, according to a letter obtained by The Washington Post.

Oversight panel Chairman Elijah E. Cummings (D-Md.) received a letter from the White House counsel Wednesday denying his request that Miller come before the committee to testify on the Trump administration’s immigration policies.

“We are pleased that the Committee is interested in obtaining information regarding border security and much needed improvements to our immigration system,” White House Counsel Pat Cipollone wrote, offering to make available “cabinet secretaries and other agency leaders” to discuss the issue.

In his original request sent last week, Cummings asked that Miller appear before the panel on May 1 “because it appears that you are one of the primary moving forces behind some of the most significant — and in my view, troubling — immigration policies coming out of the Trump White House.”

In 2017, The Post’s Rosalind S. Helderman looked at the influence that Stephen Miller, President Trump’s senior policy adviser, held inside the White House. (Bastien Inzaurralde/The Washington Post)

Few expected Miller to comply, given precedent that White House staff traditionally do not testify.

But Miller, Democrats worry, has had more power than a traditional White House staffer, particularly over immigration.

Miller was behind a controversial proposal to bus undocumented migrants to the jurisdictions of political foes of the president, Department of Homeland Security officials told The Post. He also pushed the policy that led to migrant children being separated from their parents after they crossed the southern border illegally, even if they were seeking asylum.

And Miller was reportedly the driving force behind the shake-up of the Department of Homeland Security at its highest levels, making room for the White House to install officials who will do Trump’s bidding despite concerns about legality.

Although Miller is effectively running immigration policy in the Trump administration, he is not a Senate-confirmed Cabinet secretary. That means he is not accountable to Congress the way a traditional agency head would be.