"I'm not predicting [Trump] will win, but I will say he's capable of winning in November. He has a path," Rather told CNBC's "Squawk Box," adding he does not expect the real estate billionaire to bow to pressure to be more "presidential."
"Anybody who thinks Donald Trump is going to moderate himself along the way is either slightly 'touched' or 'smoking something very expensive.' It's not going to happen," said Rather, currently host of "The Big Interview" on AXS TV.
"My own opinion again," Rather said, "Democrats who want Hillary Clinton to be president should be afraid. They should be very, very afraid."
Counting himself among the offenders, Rather said the media concentrates too much on the horse race between presidential candidates, and not enough on the substance of their proposals to change the country.
AXS TV describes itself as a partnership between founder Mark Cuban, AEG, Ryan Seacrest Media, Creative Artists Agency and CBS.
Rather left CBS in 2006 after a story he did for the program "60 Minutes" about the National Guard service of then-President George W. Bush was questioned over alleged failures in reporting procedures.