WASHINGTON — President Obama is poised to ignore stark warnings that executive action on immigration would amount to “violating our laws” and would be “very difficult to defend legally.”

Those warnings came not from Republican lawmakers but from Mr. Obama himself.

For years, he has waved aside the demands of Latino activists and Democratic allies who begged him to act on his own, and he insisted publicly that a decision to shield millions of immigrants from deportation without an act of Congress would amount to nothing less than the dictates of a king, not a president.

In a Telemundo interview in September 2013, Mr. Obama said he was proud of having protected the “Dreamers” — people who came to the United States illegally as young children — from deportation. But he also said that he could not apply that same action to other groups of people.

“If we start broadening that, then essentially I’ll be ignoring the law in a way that I think would be very difficult to defend legally,” Mr. Obama told Jose Diaz-Balart in the interview. “So that’s not an option.”