Nearly four years after he was elected on a promise of bringing change to Washington, President Barack Obama said Thursday that he had embarked on an impossible mission.

"You can't change Washington from the inside," Obama said during a live-streamed town hall in Miami which will be broadcast on the Spanish-language news network Univision tonight. "You can only change it from the outside. That’s how I got elected, and that’s how the big accomplishments like health care got done, was because we mobilized the American people to speak out. That’s how we were able to cut taxes for middle class families."

Obama had been asked about the failures of his presidency, and he cited a decision not to involve the American people more broadly in lobbying for change, a decision made early in his term by the president and chief of staff Rahm Emanuel that effective legislation would be crafted through a Capitol Hill inside game. He argued on Univision that his successes — including the health care legislation — ultimately came from mobilizing the American people around his agenda.

But the admission also seemed to undercut a central premise of his 2008 election, and even to raise questions about the urgency of re-electing the president. The comment reinforces the perception that Obama could not accomplish what he set out to do.

Obama, who earlier in the interview blamed his inability to keep his promise to pass comprehensive immigration reform in his first year on the economy and obstructionist Republicans, said that change only comes from outside Washington, adding, "that's how I got elected."