The legislation to be voted on next week satisfies demands from the most conservative lawmakers and goes further than the approach initially discussed by some House Republicans. Their proposal would have targeted only the executive actions Obama announced in November that provided deportation protections for millions of immigrants in the country illegally.

Conservatives in the GOP caucus pressed leadership to also shut down a 2012 program that has granted work permits to more than 600,000 immigrants brought to the U.S. illegally as children. Ending the program would eventually expose those young people to deportation.

Other changes would undo Obama directives to immigration agents aimed at limiting deportations of people with no significant criminal record.

“The American people were expecting the leadership to step up to the plate and not just make some symbolic gesture in trying to address what the president did back in November, but try to go a step further,” said Rep. Robert Aderholt, R-Ala. “That’s what our language does and that’s what at the end of the day I think will garner a lot of support among our colleagues.”

Obama’s directives gave temporary relief from deportation to about 4 million immigrants in the country illegally, mostly those who had been in the country more than five years and have children who are citizens or legal permanent residents. The earlier program, called Deferred Action for Childhood Arrivals, applied to immigrants brought to the U.S. illegally as children.

The immigration fight is coming to a head as Congress wraps up its first week of work after convening under full Republican control. The vote will come on a $39.7 billion spending bill to keep the Homeland Security Department running past February. The Republicans deliberately put the agency on short-term funding in a budget measure late last year so that they could deal with Obama’s immigration moves after Congress reconvened with the Senate as well as the House under their control.

There are still many uncertainties, however. A a handful of Republican moderates, including lawmakers representing heavily Latino districts, are likely to join House Democrats in opposing the legislation,

“We’ve got to deal with immigration, immigration as a whole. Reforming our system across the nation,” said Rep. Jeff Denham, R-Calif. “Just picking on the children that came here through no fault of the own I think is the wrong way to start. “

And while they may not be able to block or water down the bill, there is no guarantee the Senate will follow the House’s lead.

Even if it did, Obama could very well use his veto.

At the same time, Democrats contend Republicans are courting electoral disaster in the 2016 presidential election if they pass legislation that could alienate many Latino voters.

“It’s nothing short of breathtaking that their first move coming out of the gate in 2015 is to attack immigrants and their families,” said Frank Sharry, executive director of America’s Voice, a pro-immigrant advocacy group