Washington — President Obama appears set to go big on immigration policy, even though a unilateral move is sure to stir up furious opposition from Republicans, who will soon have full control of Congress.

That picture became clearer Thursday as news reports cited Obama administration sources saying the president’s promised executive action could provide legal status for as many as 5 million immigrants who currently lack it.

The move could win Mr. Obama resounding praise from pro-immigrant groups, but would draw intense opposition from Republicans – and further sour relations between the president and lawmakers on issues that go well beyond immigration.

Both sides agree on the need for immigration reform, which could pair new border-security efforts with an acknowledgement that many immigrants now in the United States illegally should be granted legal residency and potential paths toward citizenship.

But with legislative efforts currently stalled, Obama pledged to take actions on his own after last week’s election. His announcement could come next week.

According to reports from The New York Times and Fox News, a centerpiece of Obama’s expected announcement will be to grant a reprieve to the parents of children who are US citizens or legal residents. They would no longer need to fear deportation when they seek jobs.

Republican critics call Obama’s anticipated move a “nuclear option” on a sensitive issue that deserves to be settled through traditional legislation.

A new Christian Science Monitor/TIPP poll finds that most Americans agree with that view.

The Obama administration has said any executive action can be superseded by legislation that is signed into law, and it has encouraged the Republican-led House to act on comprehensive reforms that have passed the Senate.

House Speaker John Boehner (R) of Ohio warned last week that an executive action would “poison the well,” reducing rather than enhancing the chances for legislation to pass. Still, he acknowledged an urgent need for the nation to have immigration reform.

If critics call the move reckless politically, some also warn of a practical risk – that perceptions of a broad shift toward “amnesty” could result in a new rush of immigrants over the border at a time when officials already have their hands full.

According to Fox News, Obama will roll out a 10-part program of actions. The president has already granted to many immigrant children “deferred action” reprieves from deportation. The new actions ​would extend the policy to many parents and more young people. Other steps include measures to boost border security and to enhance pay for immigration officers in a morale-boosting effort, Fox reported.

Still unclear is how many of 11 million or more illegal immigrants in the US will be affected. The New York Times report said the administration is still weighing how many years people must have lived in the US to qualify for a reprieve.

By going big, Obama may help solidify support for the Democratic Party among the Hispanic Americans who represent a sizable and fast-growing share of the electorate.

In that light, Obama can be seen as taking a preemptive political strike against a Republican Party that very much needs to make inroads with Latino voters. Republicans showed some gains in Latino support last week in the elections, but political strategists caution that the voters who turn out for midterm elections tend to be more conservative than in presidential elections. Thus the GOP still has a big gap to close.

Obama faces his own political risk, though.

Many voters are concerned about what they view as lax federal policies on immigration and border security. And now Americans may view him as taking a partisan and unnecessary end run around Congress.

In the Christian Science Monitor/TIPP poll, taken in the week prior to the Nov. 4 elections, nearly 3 in 4 US adults said they think the executive action would “give the Democratic Party a significant advantage with the Latino community in future elections.”

But an even higher share (76 percent) said they favor Obama working “with Congress on immigration reform” rather than acting on his own. A majority of Democrats, independents, and Hispanics felt that way in the poll of 910 Americans, which was conducted by TechnoMetrica Market Intelligence.

Some members of Congress are considering responses such as trying to withdraw funding for Obama’s immigration efforts or even holding up a must-pass spending bill. Congress needs to pass a new funding bill by Dec. 11 to keep federal programs running for the rest of the fiscal year, which ends Sept. 30, 2015.