Welp, Joe Biden isn't winning the White House's March Madness pool ... 'cause the president's pick for NCAA champion -- two-seed University of Arizona -- just lost to 15-seed Princeton in the most shocking upset of the young tourney!
The Ivy League team was near 15-point underdogs against Arizona ... but as the saying goes, that's why you play the game. The Tigers ultimately won 59-55. The Wildcats were up one at the half, but scored a paltry 24 points in the second half, and couldn't buy a bucket late in the game.