Americans will be "f**ked" if Barack Obama gets re-elected ... this according to Beach Boys singer Bruce Johnston.
Bruce was signing autographs for fans in New York yesterday when the conversation turned political.
"Obama's an a**hole, "Johnston says ... adding, "Unless you're interested in never having any money and being socialized."
But Johnston was an equal opportunity disser -- saying, "And who's the Republican a**hole?"
"Our guy isn't any good."
He continued, "You got Reagan and Tip O'Neill ... those are the last two good guys."
"Wait 'til Obama doesnt have to try anymore," Bruce added ... "you're f**ked."