Leaders of UK, France and Germany all say multiculturalism has failed

Yesterday French President Nicolas Sarkozy said that "... clearly yes, it is a failure" where the "it" referred to multiculturalism. The other "big 3" European leaders, David Cameron of Britain and Angela Merkel have also said that experiments in their respective cultures in multiculturalism have failed. When will the Democrats in the U.S. realize this? Why can't they look at the coins in their pockets and see that the solution is "E Pluribus Unum" - out of many - one.