Stephen Miller is a survivor in President Trump’s White House.

The young policy aide has solidified his influence, even as would-be allies such as Stephen Bannon have been forced out of the West Wing.

In just the past month, he played a key role in developing the administration’s new travel ban, pushed Trump to scrap an Obama-era program for young immigrants living illegally in the U.S. and argued for a historically low refugee cap.

He has also helped write the president’s major speeches, from the inaugural address to Trump’s response to the mass shooting in Las Vegas, and is among a group of aides that often travels with the president on Air Force One.