From the WSJ today:

Hit hardest would be the “95% of working families” Mr. Obama keeps mentioning, usually omitting that his no-new-taxes pledge comes with the caveat “unless you use energy.” Putting a price on carbon is regressive by definition because poor and middle-income households spend more of their paychecks on things like gas to drive to work, groceries or home heating… In other words, Mr. Obama expects a much larger tax increase than even he is willing to admit.