Overpromising? Not really. Obama himself allegedly threw around numbers in the millions when he spoke to immigration activists about this a few weeks ago.

Politico has a fine reminder today that everything he says, including what he says about his own presidential powers, can be trusted only up until the moment when the politics of the situation change and not a second longer.

President Barack Obama insisted for years that he had absolutely no legal authority — none whatsoever, zero, zilch — to slow deportations on a broad scale…

Obama’s pledge to use his executive powers by the end of the summer marked both a dramatic reversal in rhetoric and a major strategic shift on immigration. The president is no longer emphasizing his own powerlessness but rather his determination “to fix as much of our immigration system as I can on my own, without Congress.”…

Even immigrant rights advocates, who were on the receiving end of the White House denials for years, were surprised by his abrupt and enthusiastic move toward executive action in June after House Speaker John Boehner (R-Ohio) ruled out a legislative overhaul of immigration this year. Activists had gotten so fed up in recent months that some tagged the president as the “deporter-in-chief” and demanded that he shift immediately from a legislative strategy to an administrative one.

“The way they talked about it was, ‘There’s nothing we can do, only Congress can solve it, we don’t have the authority,’” said Lorella Praeli, director of advocacy and policy for United We Dream. “That is very different from what they are saying today. It is completely different.”

So it is. Either he was lying all along, falsely claiming he believed his powers were modest in the name of enticing Republicans into an amnesty deal that would give the White House bipartisan cover, or he’s lying now but is determined to push ahead because he’s decided that the politics of a mass executive amnesty are a net positive for Democrats long-term. Watch the second clip below, from last November, when a heckler demanded that he use his executive authority to legalize the untold millions of adult illegals inside the U.S. I can’t, said O. We’re a nation of laws. We are?

The deeper mystery is why he thinks this is a political winner now for Democrats. The long-term game is obvious — pander to Latinos as much as possible — but the short-term angle is confounding, especially with anxiety about the border crisis high. Case in point:

According to the poll, 51% now say the government’s focus, when it comes to immigration policy, should be formulating a plan to stop the flow of undocumented immigrants. Forty-five percent say the top priority should be developing a plan that would allow undocumented immigrants who have jobs to become legal residents.

That’s a change from February, when Americans said 54%-41% that legal status trumped border security.

With public sentiment moving towards security and away from legalization, he’s going to drop an amnesty atomic bomb for millions of illegals right before the midterms? C’mon. Gutierrez gets asked about that in the first clip and doesn’t even contest that the politics are dodgy. His answer is that we can’t put politics above doing what’s right for migrants, which is precisely what you’d expect a guy whose only loyalty is to “the immigrant community” to say. But what about O? At a minimum, if he’s really thinking about bringing America’s refugee apparatus to Central America to make immigration faster and safer for child migrants, you’d think he’d want to hold off on any political sudden moves for illegals who are already here. Mickey Kaus argues, in fact, that Obama’s painted himself into a corner: If he goes big on executive amnesty now, he might doom red-state Democrats in November. If, despite his promises, he goes small, Gutierrez will be back on MSNBC the next day blubbering about Obama’s final betrayal or whatever. Kaus thinks O will have no choice but to take the medium approach, something short of the five million Gutierrez wants but with a promise to finish the job and amnestize the rest of the group next year when the politics aren’t quite so hot. Unless the White House has data suggesting that a big amnesty now will send turnout by Latino voters this fall skyrocketing, I don’t see how he can follow any other approach.