Obama blames political shift for delay on immigration

But Obama also denied that he put off action to help vulnerable Senate Democrats in the November election. "That's not the reason," he said.

"I'm being honest now about the politics of it. This problem with unaccompanied children that we saw a couple weeks ago, where you had, from Central America, a surge of kids who were showing up at the border, got a lot of attention. And a lot of Americans started thinking, 'We've got this immigration crisis on our hands,' " Obama said.

Obama said the surge in June has dropped off throughout the summer and is now lower than it was last year.

"But that's not the impression on people's minds," he said. "When I take executive action, I want to make sure it's sustainable."

When Todd asked if that meant that he didn't want to take action because it was unpopular, Obama said, "What I'm saying is that I'm going to act because it's the right thing for the country. But it's going to be more sustainable and more effective if the public understands what the facts are on immigration, what we've done on unaccompanied children, and why it's necessary."