To hear The Donald tell it, he totally trumps President Barack Obama as a messenger and far outweighs Mitt Romney as a businessman. Riding a surge in the polls recently, Donald Trump let loose on CNN’s “State of the Union” on Sunday, blaming Mr. Obama for soaring oil prices and disparaging Mr. Romney, the former Massachusetts governor and his potential rival for the 2012 Republican nomination, as “basically small business guy.” Showing his usual flair for letting it rip, Mr. Trump said the U.S. had become “a laughingstock throughout the world” under Mr. Obama. Were he president, Mr. Trump said,...