Prez Obama: Awesome Freestyle Rose Garden Rap by 'Hamilton' Brainchild

This may be the best video in March ... "Hamilton" creator Lin-Manuel Miranda taking cues from President Obama in the White House Rose Garden and freestyling in a way that would make Tupac proud.

It's pretty incredible ... the Prez held up cue cards with topics ranging from Obamacare, the Supreme Court, NASA and immigrants, and Lin-Manuel killed it.

Obama's impressed enough to drop a phantom mic at the end.