Rep. Jonathan Jackson says Tupac Shakur's murder verdict brought back a night he'll never forget ... the night he saw Pac clinging to life.

Charlie caught up with the Illinois congressman on Capitol Hill Tuesday after Duane "Keffe D" Davis was found guilty of first-degree murder in Tupac's 1996 killing.

Jackson says he was at the Mike Tyson fight that night with his father, Rev. Jesse Jackson ... and the two later went to the hospital, where Jonathan saw Tupac in "pretty bad shape."

"I've prayed for this day," Jackson said of the verdict ... but he wasn't exactly giving investigators a victory lap.

Jackson pointed to Keffe D's own public admissions over the years ... saying cops should've cracked the case decades ago if they'd done proper police work and believed witnesses.

He then zoomed out ... saying young Black men too often don't get the "full weight of justice" when they're victims -- pointing to Tupac, Biggie Smalls and Nolan Wells.

Charlie asked whether Tupac's murder would've been solved sooner if he were white. Jackson wouldn't go that far ... but said authorities damn sure could've put more effort into the case.

Nearly 30 years later, Tupac finally has a murder conviction tied to his death ... Jackson just wishes justice had moved a hell of a lot faster.