The actor -- and rumored Texas Governor hopeful -- just posted a video addressed to these United States ... and it's chock-full of that classic MMC charm, but underneath all the charisma and showmanship, Matt's actually got a great sentiment he's trying to impart.

Check it out ... the guy's talking all about how we, as a country, need to constantly be reminded that we're striving toward an ideal, and that we should be working toward that in harmony with one another. He even suggests what sounds like a new national anthem.

Of course, the backdrop of his remarks here is a lot of renewed chatter on what America means today ... and for whom. Consider Macy Gray's call for a revamped flag, and more recently ... when Olympic hammer thrower Gwen Berry turned her back on the flag/anthem.

In Matt's eyes ... those feelings are not something to shy away from, but to embrace -- and work to get better for everyone's sake. He acknowledges we should be attempting to be as inclusive in our individual pursuits ... because it really benefits everyone, and reminds us -- we're Americans, united as one. We know ... it's got politico prose written all over it.

Speaking of that ... Matt has slipped in favorability of late in a hypothetical run between himself and incumbent Gov. Greg Abbott (a Republican) -- but not by much, just 1 point.

He's still doing a heck of a lot better than actual politicians who are rumored/already set to run as well ... including Beto O'Rourke and Don Huffines. So, all things considered -- he's being eyed as the favorite to go head to head with Abbott.