A year into his presidency, President Obama faces a polarized nation and souring public assessments of his efforts to change Washington, according to a new Washington Post-ABC News poll.Nearly half of all Americans say Obama is not delivering on his major campaign promises, and a narrow majority have just some or no confidence that he will make the right decisions for the country's future.More than a third see the president as falling short of their expectations, about double the proportion saying so at the 100-day mark of Obama's presidency in April. At the time, 63 percent said the president had accomplished a "great deal" or a "good amount." Now, the portion saying so has dropped to 47 percent.