‘Trump lives in abject fear of his base — and Robert Mueller’: MSNBC anchor says it’s turning him into a ‘Mad King’
Robert Mueller in 2012 (U.S. Embassy Tallinn)

MSNBC anchor Nicolle Wallace explained how President Donald Trump's worst fears are turning him into a "Mad King" during analysis following the president's Oval Office demands for his border wall.

Wallace, who served as White House director of communications during the George W. Bush administration, joined Rachel Maddow with Chris Hayes.

Wallace said Trump "doesn't even care" about actually getting a bill passed to build his wall.

"It's something simpler than that, more primal, because it's Trump, right?" she suggested.

She said she had talked to "a close Trump ally" recently.

Nicolle said she asked what Trump was doing.

"He said [Trump] lives in abject terror of his base and Robert Mueller," she revealed.

"You can't control what Robert Mueller is doing, but the base he can keep," she explained. "The base feels that way, they feel that intensity and so you can keep them ginned up."

She also disclosed something else she'd heard from somebody close to the president.

"A friend of his has said, at other points in the presidency, that he is the 'Sun King' and anything that obscures his access to the rays of sunlight drives him mad -- so sort of like a Mad King," Wallace added.