President Donald Trump put Stephen Miller in charge of the White House on Friday. The elevation of his longtime aide pushes Susie Wiles aside only days after Republicans lost both chambers of Congress.

Miller who has been serving as deputy chief of staff starts Monday November 9. Trump said Wiles is moving to his political organization after what he called an outstanding run in the West Wing.

People familiar with the talks said Wiles handed in her notice Thursday evening. She was the first woman in the post and stayed longer than any chief of staff from Trump's earlier presidency.

A trusted aide moves up

Miller has worked with Trump since the 2016 campaign and became a central figure on immigration and border policy. Allies cast him as a loyal operator who will push the president's agenda hard through the closing stretch of the term.

Trump posted the change on social media Friday afternoon. He praised Wiles and called Miller one of his most trusted advisers.

Miller thanked Wiles for years of help and friendship. He said the task ahead is to support the president and defend the country with full force.

Democrats push back

House Minority Leader Hakeem Jeffries demanded that Miller be removed instead of elevated. Senate Minority Leader Chuck Schumer said the pick showed Trump ignored the midterm message from voters.

The shake-up lands as Democrats prepare to take control of Congress in January. Several Democratic lawmakers have already signaled investigations of Trump officials after their sweep at the polls.

Wiles said serving in the White House was the honor of a lifetime. She added that her commitment to the president will continue in her new role.