The whole thing begs the question ... Is O.J. trying to take out Trump? Sure seems that way.

The 73-year-old ex-con says his new rant was inspired by a golf outing with a buddy who was sporting a "Make America Great Again" hat ... which really rubbed him the wrong way.

"I was teasing him a little bit," Juice admits ... "He said 'Man, why does everyone get on my case when I wear this hat?'"

O.J. explained it this way... "I think 'Making America Great' is great. It's the 'Again' that bothers me."

Simpson is clearly offended by the slogan -- and tries to explain why America has BEEN great under several U.S. presidents -- he names both Republicans and Democrats, including Bush and Obama.

"Through all those presidents, America was great. We were the #1 nation there is."

"All of these politicians today, they're standing on the shoulders of the giants who ran this country before them."

Simpson ended his golf-course rant by encouraging people to vote.

So, does this mean Simpson is supporting Joe Biden?

Unclear ... but Simpson did say something interesting when asked in 2018 if he would have voted for Trump in the 2016 election.

"Somebody asked me if I'd have voted for him ... Probably not, but I only know two of my friends I'd vote to be president."

"Some of my best, best besties I would not vote to be president."