A surge of civic pride has pushed patriotic lessons into classrooms across the United States. Now comes the backlash. A small minority of parents, teachers and students — tentative at first, but getting louder — is standing up to denounce the new boosterism. The Pledge of Allegiance is divisive, they say. The Star Spangled Banner, too hawkish. And the lessons on America, land of freedom and justice? Jingoism. Propaganda. Much of the ire has focused on the Pledge of Allegiance, newly prominent in school after school. US Education Secretary Rod Paige has called for every student — from Maine to Hawaii — to face a flag at the same time today and put hand over heart in unison. ‘‘Join me ... and other proud Americans across the country in showing our patriotism by reciting the Pledge of Allegiance,’’ he urged.