President Barack Obama's announcement of immigration changes that will protect nearly five million people living illegally in the US from deportation has infuriated Republicans.

It has also left the party scrambling for a response that will not undermine their prospects in the 2016 presidential election.

Mr Obama's measure, which will make nearly half of those living in America illegally eligible for work permits, has been criticised by Republicans as an amnesty for lawbreakers and abuse of presidential powers.

House of Representatives speaker John Boehner accused Mr Obama of "damaging the presidency itself" with his unilateral action on immigration.

"I will say to you, the House will, in fact, act," Mr Boehner said. "We will listen to the American people, we will work with our members and we will work to protect the Constitution of the United States."

But whatever action the Republicans take will mean they must balance the demands of irate conservatives without alienating moderates, Hispanics and other voters.

The other question vexing Republicans is how to undo an action set to take effect without Congress doing anything, with no obvious legislative vehicle for doing so and Mr Obama able to veto any legislative solution they derive.

Conservative lawmakers are pushing to insert language in upcoming must-pass spending Bills to block Mr Obama's order. Party leaders warn that could lead to a government shutdown.

Numerous Republicans have discussed suing the president over his immigration orders, or expanding a lawsuit already planned over the health care law to include immigration. Yet they fret it would take too long and would not have the effect of blocking Mr Obama's orders from going into effect.

Others said Republicans had an obligation to try to craft their own legislation. But chances of success seemed remote, at best.

In a televised address to the nation, Mr Obama defended his actions and challenged Republican lawmakers to focus their energy not on blocking his measures but on approving long-stalled legislation to take their place.

"To those members of Congress who question my authority to make our immigration system work better, or question the wisdom of me acting where Congress has failed, I have one answer: Pass a Bill," Mr Obama said, flexing his presidential powers just two weeks after his political standing was challenged in the midterm elections.

Despite Mr Obama's challenge to Republicans to pass a broader immigration Bill, his actions and the angry Republican response could largely stamp out those prospects for the remainder of his presidency, ensuring the contentious debate will carry on for some time.

While Mr Obama's measures are sweeping in scope, they still leave more than half of the 11 million people living illegally in the US in limbo.

The president announced new deportation priorities that would compel law enforcement to focus its efforts on tracking down serious criminals and people who have recently crossed the border, while specifically placing a low priority on those who have been in America for more than 10 years.

Mr Obama spent months trying to gain a House vote on the Senate Bill, frustrating immigration advocates and some Democrats who wanted him to instead take action on his own.