The bill -- backed by conservatives who are itching to confront Obama on immigration, but criticized by Democrats who say it puts the nation's security apparatus at risk -- has already been the subject of veto threats from Obama's White House.

It might not get that far. Senate Republicans could struggle to find the 60 votes necessary to clear procedural hurdles and bring the bill to a vote.

And on Tuesday night, one of the planned amendments was running into resistance from moderate Republicans.

House Republicans plan Wednesday to hold votes on a series of amendments that would not only undo Obama's move late last year to block the deportation of undocumented parents of U.S. citizens, but also unravel several of his earlier immigration moves -- such as allowing children who were brought into the country by their parents to stay.

Illinois Republican Rep. Adam Kinzinger told CNN the amendment to roll back the Deferred Action for Childhood Arrival program, created in 2012 to permit so-called "dreamers" to remain in the United States, went too far for him and he'll oppose it.

"There's a lot of us that are concerned with the language," he said.

If the amendment fails, leaders who pleased conservatives by allowing its consideration could struggle to get those hard-liners to support the entire package -- especially since House Democrats have vowed to oppose the measure.

Those Democrats claim the GOP's approach is irresponsible, saying the Department of Homeland Security, which also oversees immigration enforcement, is dealing with new fears in the wake of the Paris attacks last week.

"These are poison pill amendments clearly designed to placate the extreme right wing of the Republican Party. We are here to say to say we don't agree with it. The atrocities in Paris, the bombing in Colorado, the other things that are occurring dictate a focused approach on homeland security," Mississippi Democratic Rep. Bennie Thompson said at an event with dozens of House Democrats on the Capitol steps on Tuesday.

House Speaker John Boehner set the stage for the fight last year when Republicans agreed to fund the department through February while funding the rest of the government through most of 2015.

One GOP amendment would block the agency tasked with carrying out the president's order from spending any of the fees it collects or issuing any new work permits.

In another move, the bill could bar any of those who were allowed to stay any chance to renew their status -- potentially setting up tens of thousands of deportations of young undocumented workers and students.

Another GOP amendment changes guidance the Obama administration issued in 2011 putting a special priority on deporting criminals, especially sexual offenders.

Pending amendments aside, the underlying Homeland Security funding bill itself is a bipartisan deal negotiated by House and Senate appropriators. It includes new money for border security, the Secret Service and other items Homeland Security Secretary Jeh Johnson has said are key to the agency's ability to protect Americans.

The immigration showdown came up Tuesday when Obama and Vice President Joe Biden hosted 19 congressional leaders at the White House.

In a read-out of the meeting, the White House said Obama called for the Homeland Security Department to be funded "without delay."

"The president underscored there are priorities that rise above politics -- including keeping Americans safe by promptly and fully funding the Department of Homeland Security without delay so the men and women working there can operate with the confidence they need," the White House said.

Separately, Boehner's office said the Ohio Republican made clear that the immigration provisions, undoing Obama's executive actions to forestall deportations for the undocumented parents of U.S. citizens, as well as his previous move to prevent the deportation of young people who have spent most of their lives in the United States, won't be dropped from the bill.

"The bill will include amendments to stop the president's unilateral actions on immigration, and the speaker reminded the president that he himself had stated publicly many times in the past that he did not have the power to rewrite immigration law through executive action," Boehner's office said.