President Obama reportedly asked historians for defense vs. ' class warfare ' attacks . Zelizer : There 's no way for historians to avoid controversy over the issue of inequality . Two Democratic presidents -- Obama and LBJ -- found different ways to raise the issue , he says . Princeton , New Jersey ( CNN ) -- Zelizer : America 's economic stagnation increases the difficulty of understanding inequality .
President Obama reportedly asked historians for defense vs. ' class warfare ' attacks . Zelizer : There 's no way for historians to avoid controversy over the issue of inequality . Two Democratic presidents -- Obama and LBJ -- found different ways to raise the issue , he says . Zelizer : America 's economic stagnation increases the difficulty of understanding inequality .