Arnold Schwarzenegger Reacts to Charlie Kirk's Death

Arnold Schwarzenegger is blaming politicians -- and social media -- for the deep divide America is facing following the assassination of Charlie Kirk ... and calling on younger generations to help heal the divide.

The 'Terminator' star spoke at University of Southern California's Democracy Day Monday and expressed his shock and sadness over Charlie's murder, calling him a "great communicator" who could debate people who both agreed and disagreed with him.

Check out the clip -- Arnold said there's plenty of blame to go around ... from social media and mainstream media to politicians on both sides of the scale, and warns America needs to "be careful" about where things are headed. He reasons ... "We have to be very careful that we don't get any closer to the cliff because when you fall down the cliff, down there, there's no democracy."

That's where the "people power" of students comes in, he says. The actor-turned-politician says USC students can lead by example, suggesting Democratic and Republican organizations come together to show other similar groups it can be done ... and perhaps some ongoing issues can be solved.

He preaches ... "Each and every one of you in here can make a difference. You can show leadership. This is about leadership."

Arnold gave the moving speech just days after Charlie was murdered at Utah Valley University during one of his famous college campus debates.

While the suspected shooter -- Tyler Robinson -- is reportedly from a right-wing Mormon household ... authorities say he recently started sharing strong criticism about Republican ideals, and Charlie, specifically.