Stark divisions between House Republicans have threatened the success of comprehensive immigration reform this year, Sen. Ben CardinBenjamin (Ben) Louis CardinDems demand Tillerson end State hiring freeze, consult with Congress Former New Mexico gov: Trump's foreign policy is getting 'criticized by everybody' Dems put hold on McFarland nomination over contradictory testimony: report MORE (D-Md.) charged Sunday.

The Maryland Democrat said he's hopeful Congress can resolve its differences and pass immigration legislation before the midterm elections, but he warned the GOP's fear of highlighting party discord could sink the process.

"I think that there's so much infighting in the Republican Party in the House, that they're just concerned that they'll show that fracturing of the party, and therefore the immigration bill is one of the casualties," Cardin said in an interview on "Fox News Sunday."

Appearing on the same show, Sen. Roy BluntRoy Dean BluntDems push for more money for opioid fight Trump asked Senate Republicans to end Russia election interference investigation: report An overlooked solution to the opioid epidemic MORE (R-Mo.) defended the reluctance of House Republicans to move forward on the issue. Echoing Speaker John BoehnerJohn Andrew BoehnerJohn Feehery: A political forest fire Trump's pick for Federal Reserve chief is right choice at right time The two-party system is dying — let’s put it out of its misery MORE (R-Ohio), Blunt blamed President Obama, who is vowing to escalate his use of executive powers, for any delay.

"The House reluctance has a lot of things that drive it, and one is the president's constant talking about how he can use his pen and his telephone," Blunt told Fox.

"How the president thinks that helps in any negotiation with Congress to do anything but lead the Congress to believe that, if you don't like what has happened as part of the negotiation and there is any way at all you can work your way around it — or even declare you're going to work your way around it — you will."

The remarks come just days after Boehner suggested he's in no hurry to act quickly on immigration reform legislation, citing a distrust in Obama's willingness to implement any such law.

"The American people, including many of my members, don't trust that the reform that we're talking about will be implemented as it was intended to be," Boehner said.

Obama used his State of the Union speech last month to announce that, while he'd prefer to work with Congress to advance his priorities, he'd also act unilaterally if those issues are ignored on Capitol Hill — a message he amplified Saturday in his weekly national radio address.

"Whenever I can take steps without legislation to expand opportunity for more American families, I will," he vowed.

The remarks infuriated conservatives, who have long accused the president of overstepping his constitutional powers through executive action on a host of issues. And Boehner warned last month Obama would "run into a brick wall" in Congress if he pushes the executive-action envelope too far.

Blunt, who voted against a comprehensive immigration reform bill that passed the Senate with broad bipartisan support in June, said slowing the pace would also allow the House to address the issue piecemeal, as many Republicans prefer.

"What the House has said is, 'Let's divide these problems up. Let's solve them one at a time,' " he said. "The Senate says, 'No, one big bill or no bill at all.' And that's a pretty hard thing to resolve, particularly when the president [is vowing unilateral action]."

Democrats have rejected the Republicans' argument that a fear of Obama's implementation strategy has stalled the process.

“Republicans should be candid about putting extremism ahead of the good of the country," House Minority Leader Nancy Pelosi (D-Calif) charged.

Cardin agreed, noting voters have long supported a comprehensive solution to reforming an immigration system that all sides concur is broken.

"Our immigration system is broken. I think Americans understand that," he said. "We need to respond to it."