With budget talks just beginning on Capitol Hill, lawmakers are starting to grapple with significant disagreements over whether to reverse billions of dollars in looming mandatory budget cuts known as the sequester.

The growing discord will matter most among Republicans, who control both chambers for the first time in eight years and will be in charge of passing not only a spending blueprint, but a dozen appropriations bills needed to fund the government beyond Sept. 30.

The budget-writing process has just started, with listening sessions and private talks among lawmakers comprising most of the action, but party division over the sequester is spilling into the halls of Congress.

In one camp, mostly conservative lawmakers are calling for the spending caps mandated by the sequester to be left alone to reduce the nation’s staggering $483 billion deficit.

“Blowing through the sequester caps? Absolutely not,” Rep. Mick Mulvaney, R-S.C., a member of the House Budget Committee, told the Washington Examiner.

But many other lawmakers say the spending caps must be raised or eliminated because they would significantly harm the Defense Department and gut critical domestic programs.

“I want to get rid of sequestration,” said Rep. Mike Simpson, R-Idaho, who, as a top member of the House Appropriations Committee, is in charge of writing the energy and water spending bill.

Still other lawmakers believe the sequester should be adjusted so that money can be shuffled among programs while adhering to the sequester's spending caps.

“I am open to increasing defense as long as we stay in the overall cap, which means reductions elsewhere,” Rep. Jim Jordan, R-Ohio, told the Examiner.

Overall, the sequester is unpopular with Republicans and Democrats, but for different reasons.

The cuts, amounting to $1 trillion in federal non-discretionary spending over 10 years, were mandated in a 2011 spending deal between Congress and President Obama that aimed to reduce the growing deficit and debt.

But federal agencies said the across-the-board cuts were crippling key domestic programs, and the Pentagon issued dire warnings that reduced spending would damage military readiness and national security.

With Democrats pushing to restore spending to domestic programs and the GOP looking to boost military funding, the sequester cuts were slightly reduced in 2012.

In 2013, a bipartisan deal cut by then-House Budget Committee Chairman Paul Ryan, R-Wis., and Senate Budget Chairwoman Patty Murray, D-Wash., restored sequestered money to the 2014 and 2015 budgets by $45 billion and $19 billion, respectively.

But there is no deal in place to undo the sequester in the 2016 budget.

In a recent memo to Obama, Office of Management and Budget Director Shaun Donovan warned that unless Congress and Obama agree to make changes, the sequester will reduce next year’s defense spending by nearly $54 billion and domestic spending by $36.5 billion.

Obama, in his budget request, eliminated the sequester entirely and called for a series of tax increases. Obama’s plan is a non-starter with all Republicans because it does nothing to reduce the deficit and it raises taxes.

But the GOP unity stops there.

In the Senate, for example, multiple Republican camps are discussing options for dealing with the sequester, said Sen. John McCain, R-Ariz., who is chairman of the Senate Armed Services Committee.

McCain said he has been talking to all the groups to convince them to eliminate the pending cuts to the Pentagon.

“When the four [military] service chiefs testified before the Armed Services Committee that without repeal of sequestration, American lives, service men and women’s lives are in danger, that should be enough to convince my colleagues,” McCain told the Examiner.

McCain said he is willing to discuss restoring some domestic spending if it means fewer cuts to the military, but Sen. John Boozman, R-Ark., doesn’t agree.

“Most Republican members would like to see the Defense budget, in this very troubled world, plussed up,” Boozman said. “But they would also want us to reduce spending in other areas so we don’t increase the debt and increase the deficit.”

Congress is scheduled to pass a budget by April 15.

Rep. Tom Cole, R-Okla., who sits on both the Budget and Appropriations committees, said lawmakers are considering leaving the sequester caps in place within the budget plan.

Such a plan would be the most likely one to pass both the House and Senate he said, and it could open negotiations with Obama to undo the sequester as part of a tax-reform plan or entitlement-reform deal that the GOP is eager to achieve.

“If you try to undo the sequester in the budget, you divide your party before the negotiations even begin,” Cole told the Examiner. “And that is a huge mistake.”