Rudy Giuliani said that he doesn't think President Obama loves America and was immediately vilified for it, but numerous surveys show that liberals themselves claim to be less patriotic than conservatives do.
A Pew Research survey last year found that 46 percent of "steadfast conservatives" believed that the U.S. stands above all other countries; only 11 percent of "solid liberals" believed the same. Seventy-two percent of steadfast conservatives said they often feel proud to be an American; only 40 percent of solid liberals said they do. Gallup headlined its write-up of a 2010 survey
"One in Three Americans 'Extremely Patriotic': Republicans, conservatives, and seniors most likely to say so." According to Gallup, 52 percent of Republicans and 48 percent of conservatives called themselves extremely patriotic; only 20 percent of Democrats and 19 percent of liberals did.
That's not to say that President Obama or any other specific liberal doesn't "love America", but there's definitely a patriotism gap.