The White House Friday hit back at Republican claims that a long-delayed overhaul of America's immigration system is stalled because President Barack Obama cannot be trusted to carry it out.
Republican House Speaker John Boehner Thursday poured cold water on hopes an immigration bill could finally pass this year, saying his restive conservative caucus did not have confidence the president would implement any legislation.
But the White House said such an accusation was simply a cover for Boehner's inability to corral his members behind a push for immigration reform that Republican leaders see as vital to repairing ties with increasingly important Hispanic voters.
"If it were an issue of trust, why did Republicans block immigration reform in 2006 when the occupant of the White House was Republican president George W. Bush?" Obama's spokesman Jay Carney asked reporters aboard Air Force One.
"Was it because they didn't trust him?
"I think no -- I think the issue is because of the well-known and documented challenges dealing with this issue presents the Republican Party."
Boehner said Thursday the president's vow to go around Congress and use executive powers to implement his political program if lawmakers refuse to cooperate with him had harmed trust in the White House.
Republicans also argue that adjustments the president made to his signature health care law raise doubts over whether he could be trusted to properly carry out the requirements of an immigration reform bill.
The White House counters, however, that the president had done more to enforce America's southern borders -- the source of most illegal immigration -- than any previous US leader.
Obama, seeking a genuine second-term legacy achievement, strongly supports the Senate bill to reform immigration that passed last year, which offers a path to eventual citizenship for 11 million illegal immigrants.
The bill also includes tighter border monitoring, an overhauled work visa program and other key reforms.
Obama has been careful not to rule out less sweeping House Republican plans, and has even signalled a willingness to negotiate on his core principle of a path to citizenship.
But several observers believe that passing an immigration bill could be tough in this mid-term congressional election year.
Many conservative lawmakers view the idea of a path to citizenship as tantamount to amnesty -- and fear a backlash from their own Republican grass roots on the issue.
Republican Senate minority leader Mitch McConnell dealt a blow to hopes of immigration reform earlier this week when he also cast doubt on 2014 prospects.
But the White House said it remains "optimistic" for progress, as did Homeland Security Secretary Jeh Johnson.
"I don't have a crystal ball.... I hope it will happen in 2014," said Johnson in his first major speech since taking office in December.
"There's an emerging, evolving realization that this shouldn't be politics but that this is a problem that needs to be fixed," he said, explaining it would be better from a security perspective if the immigrants "come out of the shadows," pay taxes and undergo background checks.