Tevi Troy argues in a Politico column that the Trump administration needs someone to replace recently ousted adviser Steve Bannon.

Steve Bannon was a unique administration figure in many ways, but in another, he was part of a long White House tradition.

For the past four decades, Republicans have viewed themselves as the party of ideas—and a crucial part of that self-perception has been having a person inside the White House to serve as a conduit to conservative thinkers. Ever since Richard Nixon, Republican presidents have installed a kind of resident intellectual who can help shape the president’s vision, articulate that vision to conservative thinkers, and—importantly—warn the president of discontent from his key supporters in that conservative idea world.

Steve Bannon wasn’t a traditional liaison to that world, but there’s no question he served this function for the Trump administration, keeping it connected to at least a portion of a national ecosystem of conservative thinkers that has provided significant benefits for Republicans over the years. If he is not replaced wisely, that absence would not only represent a break from that tradition, but would create a worrisome gap for Trump as he tries to get Republicans, Congress and Americans on board for his agenda. Given this need, one of Trump’s key challenges—and opportunities—will be figuring out just what kind of person should replace Bannon.