Al Sharpton -- Obama's Falsetto Could Help Him with Voters

President Barack Obama's kick ass rendition of Al Green's "Let's Stay Together" at The Apollo last night was GREAT for his campaign ... because it humanizes him to voters ... this according to Al Sharpton.

The Rev -- who ALSO killed it on stage at The Apollo a few years ago with a GREAT rendition of James Brown's "I Feel Good" -- was out in NY today when we asked for his expert opinion.

Rev told us, "The President has SKILLS ... he showed real skills ... he sang an almost perfect falsetto."

He added ... "[The performance] humanizes him, and it makes people understand he knows the words to the song. How many presidents actually know the lyrics to the Al Green song?"