President Donald Trump wants to increase military spending, potentially by $54 billion in 2018 and also add as much as $30 billion to the Pentagon’s 2017 budget, potentially boosting defense spending to levels not seen since the heights of the Iraq and Afghanistan wars.

The details aren’t in yet. But budget-conscious conservatives and good government groups are already halfway-convinced that the extra money—up to $30 billion more in 2017 and another an $54 billion in 2018—is about to go to waste. Meanwhile, defense hawks have started complaining that a mere $603 billion in annual military spending (plus $30 billion to $60 billion in “supplemental” cash) is too little, too late.

Even the smaller boost to military spending could set off a civil war within Republican ranks. Sen. John McCain, an Arizona Republican and the Senate’s leading defense hawk, said that the Trump administration’s spending increase was little more than a gimmick.

“It is misinformation at its best,” Sen. John McCain, an Arizona Republican and the chairman of the Senate Armed Services Committee, McCain told The Daily Beast. The Obama administration had already planned for a major Pentagon budget boost next year; Trump’s proposal is just a bit more than Obama’s. “It’s a three-percent increase and that is minimal and will never match up with what we need to repair the damage of the last eight years. They have $603 billion, we need $640 billion. So it’s about $37 billion short.”

There’s no guarantee Congress will give Trump his extra military spending—or that the administration will wisely spend an extra appropriations it does manage to force past House deficit-hawks and Senate Democrats. Trump is scheduled to review the Navy’s newest aircraft carrier and the Air Force’s most advanced stealth fighter jets visit a shipyard and an Air Force base on March 2—an apparent attempt to reinforce his military credentials as the spending battle looms.

“This budget… will include a historic increase in defense spending to rebuild the depleted military,” Trump told a group of governors at the White House on Feb. 27. The Defense Department’s budget is separate from those of the Veterans Administration and the Department of Energy, which helps to develop and maintain America’s nuclear weapons.

Trump said he would pay for the Pentagon’s financial boon by cutting funding for other federal agencies. The Environmental Protection Agency and the State Department’s foreign-aid accounts are reportedly first in line for deep cuts. “We’re going to do more with less,” Trump told the governors.

But even entirely eliminating both departments wouldn’t compensate for the Defense Department’s plus-up. The State Department and USAID currently spend about $50 billion. The EPA spends around $8 billion.

And as it stands, the military’s extra money would exceed legal limits. To enact Trump’s spending plan, Congress will have to amend or repeal the 2011 Budget Control Act—a move that, under current Senate rules, would require the consent of at least eight Democrats. The law caps the Defense Department base budget, which doesn’t count supplemental funding, at $512 billion in 2018. The Obama administration sought, and Congress approved, a higher cap in 2017.

Trump’s spending outline represents the opening move in months-long budget negotiations. Ultimately, the House and Senate write the actual budget.

The 2018 fiscal year begins this in October, but Congress has been late enacting budgets every year since 2009. Amending or repealing the Budget Control Act could further slow the process. Likewise, environmental and humanitarian groups will probably have something to say about any plan to cut the EPA and foreign aid.

Trump aims to add $54 billion to the $546-billion Pentagon base budget the Obama administration had projected for 2018. The administration also wants to add as much as $30 billion to the $60-billion supplemental budget that President. Barack Obama asked for as part of his final budget proposal for 2017.

All told, the military could spend around $620 billion in 2017 under Trump’s plan and, if the trends hold when it comes to supplemental budgets, around $690 billion in 2018. The modern peak for U.S. defense spending was in 2010, when Congress passed a $600-billion base budget and also added a $130-billion war supplement.

But that was back when there were hundreds of thousands of troops in the field. Today, around 15,000 U.S. troops are deployed in Iraq and Afghanistan, down from nearly 300,000 in 2008.

The record 2010 budget paid the hefty tab for combat operations in Iraq and Afghanistan, but largely neglected maintenance for tens of thousands of war-weary ships, planes and vehicles. The armed forces have reported a maintenance backlog totaling tens of billions of dollars. The Navy has grounded two-thirds of its F/A-18 fighter jets until it can afford to fix them. Entire Army divisions are officially unfit for high-intensity combat.

The spending plan fulfills, in part, Trump’s campaign pledge to “make the military great again.” But there’s a high risk that Pentagon planners could squander much of the windfall.

Trump’s push for a modernized nuclear arsenal—an initiative that counterproliferation experts have decried as destabilizing and wasteful—could consume a significant portion of the extra defense spending.

Considering that Trump has vowed to expand the Navy from today’s 275 ships to 350 ships and also grow the Air Force fighter fleet, the military might pour much of its extra cash into underperforming new weapons programs such as the F-35 stealth fighter and the Littoral Combat Ship, rather than using the bonus to pay for the most urgent, but less politically sexy, maintenance needs.

“Arbitrarily increasing the Pentagon’s budget without first tackling any meaningful reforms will only result in more of the same,” Dan Grazier, an analyst at the Project on Government Oversight in Washington, D.C., told The Daily Beast. “We’ll get more F-35’s that aren’t ready for combat, more LCSs that will end up stuck in port or out to sea, and more money wasted on overhead at the Pentagon.”

Likewise, Trump’s reliance on the 2017 supplemental to quickly boost the Pentagon’s budget could backfire. Even under the best of circumstances, it could take Congress months to approve any new appropriation, by which time the 2017 fiscal year could be nearly over. The military could find itself with too little time to spend the extra $30 billion.

For that reason, one military sourceformer Pentagon official said Trump should propose a smaller supplemental for this year—one the Defense Department can actually spend. Otherwise “you’ll leave half the money on the table, and set up a history of waste which could hurt you down the road,” a the former Pentagon official told The Daily Beast on condition of anonymity.

Even the smaller boost to military spending could set off a civil war within Republican ranks. Sen. John McCain, an Arizona Republican and the Senate’s leading defense hawk, said that the Trump administration’s spending increase was little more than a gimmick.

“It is misinformation at its best,” McCain told The Daily Beast. “It’s a three-percent increase and that is minimal and will never match up with what we need to repair the damage of the last eight years. They have $603 billion, we need $640 billion. So it’s about $37 billion short.”

But there are also a faction of deficit hawks in Trump’s party. Some including Deficit hawks like Arizona Republican Sen. Jeff Flake—also an Arizona Republican—are waiting for more details about potential offsets to the spending before making a judgement. As he rushed off to vote Monday evening in the Capitol, Flake told The Daily Beast that he hadn’t been caught up to speed on the proposal yet.

But others, such as conservative Michael Ostrolenk, a policy adviser for the Pentagon Budget Campaign, are bracing for a battle that will define the right for years to come.

“This is part of the battle for the soul of the Republican Party,” Ostrolenk said. “Rhetorically, they’ve been in favor of limited government, reducing spending and dealing with the debt—versus this present administration, which doesn’t seem to care much for these three things.”

“It’s a battle between the Tea Party movement and Trump’s worldview … tax cuts, a trillion dollars in infrastructure spending—that’s what led to the creation of the Tea Party. We can’t spend like drunken soldiers. And that’s not just when Democrats are in power.”

“The Pentagon doesn’t need this increase,” said Benjamin Friedman, a research fellow in defense studies at the free-market Cato Institute in Washington, D.C. “You can get the money needed to improve readiness from within the current budget. The wars we are fighting and the threats we face, contrary to much rhetoric, are not sufficient to warrant even our current military spending, let alone a boost.”

The next step in the budgeting process is for the Trump administration to release formal budget proposals. “In a normal transition, these numbers could come some time in March,” the former Pentagon official said. “But we are not in normal times.”

—with additional reporting by Noah Shachtman