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White House press secretary Josh Earnest pointed the finger squarely at House Republicans on Thursday for President Obama's decision to take executive action on immigration reform.

"It's House Republican leaders that have perpetuated the terrible problem that everyone acknowledges exists," Earnest said. "The president is going to use the authority that he has to try to solve some of those problems."

Appearing on Fox News Channel's "America's Newsroom" ahead of Thursday's prime-time address, Earnest defended the timing and scope of the president's upcoming action: "The Republican speaker of the House, who has blocked common sense immigration reform for the last two years, was asked right after the election whether or not he would commit to bringing up immigration reform legislation in the new Congress. And he wouldn't do it.

"If Republicans do get their act together, if John Boehner changes his mind and does decide to work in collaborative fashion, in bipartisan fashion… to back something that the whole country supports, then the president would be happy to sign that bill," Earnest said. "And if it meets the principles that are included in the Senate bill that's already passed, the president would be happy to sign that bill and have it supersede the executive action that he's announcing tonight."

Pressed for details of Obama's plan, Earnest refused to "get ahead of the president" but noted that the White House would "make clear what the legal justification is for those steps and that legal justification will be entirely consistent with steps that were taken by President Reagan and President George H.W. Bush."

Earnest refuted critics' claims that the president is hoping to provoke a "dramatic" Republican reaction to his executive action, noting that despite GOP efforts to defund ObamaCare "not once have you heard me or anybody else who works in a senior position of this administration come forward and say that has poisoned the well and because of that vote we're no longer going to work with House Republicans.

"We're going to disagree on things," Earnest said. "I'm not suggesting that Republicans should fold on their principles. What I'm suggesting is we shouldn't allow a disagreement over one issue to be a deal breaker over every other issue."