Arizona Sen. John McCain, who has clinched the Republican presidential nomination, had former Mayor Rudy Giuliani laughing in the limo after a McCain fundraiser at the 21 Club Tuesday night in Midtown. McCain hinted to the New York Post that Giuliani could get a spot in a McCain administration. “Oh yeah. He’s a great American. He united America,” the senator told the paper. “Lobbyists for McCain,” a satirical protest group patterned after Billionaires for Bush, tried unsuccessfully to crash the party.