Defense Secretary Lloyd Austin and Air Force Gen. Charles “CQ” Brown, chairman of the Joint Chiefs of Staff, meet with House Speaker Mike Johnson, R-La., at the Capitol Building in Washington, D.C., Nov. 1, 2023. (Cesar J. Navarro/U.S. Air Force)

WASHINGTON — The U.S. military’s top general warned senators that if they keep failing to pass a defense budget for fiscal 2024, it will cause a funding shortfall that could block the Pentagon from properly modernizing the armed forces.

“We owe our service members the tools they need to be successful,” Air Force Gen. Charles “CQ” Brown, chairman of the Joint Chiefs of Staff, wrote in a letter to the Senate Appropriations Committee. “We have asked them to modernize and accelerate the future capabilities they need to continue to deter and project credible combat power. We need full appropriations to stay ahead of pacing, acute, and unforeseen challenges.”

Fiscal 2024 began Oct. 1, but government agencies are still being funded through a continuing resolution, which is a short-term stopgap measure that extends funding at 2023 amounts until Congress can pass a budget. The temporary funding will end for the military on Feb. 2.

House Speaker Mike Johnson, R-La., caused new concern this week when he told other lawmakers that he might try to extend the continuing resolution — known as a CR — to cover the rest of fiscal 2024 if Congress can’t agree on a budget by February, according to a Bloomberg report. Brown said such a move would be disastrous for the armed forces.

“[The Pentagon] has never operated under a yearlong CR,” Brown wrote in his letter to the committee, which creates the legislation to authorize government funding. “ln a CR, the [Defense Department’s] actual buying power is significantly impacted and degraded. Failing to fully fund the DOD would disrupt important progress.”

For example, Brown wrote a full-year CR would open a military personnel budget shortfall of almost $6 billion that would “exacerbate recruiting and retention challenges.” The Army, Navy and Air Force all failed to meet their recruiting targets in 2022 and 2023.

“DOD would be forced to delay service member moves and slow recruiting to offset the costs of the 5.2% pay raise for the military,” the general wrote.

Brown, who succeeded Army Gen. Mark Milley as chairman of the Joint Chiefs in September, also cautioned sticking with a continuing resolution would prevent the military from working on critical security projects such as shipbuilding and nuclear modernization.

“A yearlong CR would delay … the procurement of the [new] B-21 Raider and could prevent the award of the second Columbia-class, ballistic-missile submarine,” he wrote. “Additionally, a yearlong CR would cancel or delay ship depot maintenance availabilities, impacting readiness.”

The continuing resolution now funding the government is the second since the start of fiscal 2024. The first one expired in mid-November and was quickly followed by the second, but in-fighting among House Republicans is creating doubt that the lower chamber can agree on budget figures to authorize full government funding. The far-right Freedom Caucus this week softened its demands for more than $100 billion in federal cuts for 2024, mostly from domestic programs. In March, President Joe Biden requested a total budget of $6.8 trillion for 2024, which included $842 billion for the Pentagon. In October, Biden further asked for a supplemental budget request of about $100 billion, which would provide more aid to Ukraine and Israel and add new investments for the U.S. defense industry.

“Passing a full-year funding bill and the president’s national security supplemental request would prevent these devastating impacts,” Brown concluded in his letter. “It would also provide funding for critical weapons and equipment for our allies and partners while replenishing depleted DOD stocks and providing for robust investments in the defense industrial base.”

If Congress fails to pass additional funding measures by Jan. 20, when CR funding for all agencies except the Defense Department runs out, the federal government will face a partial shutdown. The Pentagon would have funding for an additional two weeks.