WASHINGTON — Top US military officials told lawmakers Thursday their services have been squeezed by budget instability and spending caps — and that under sequestration cuts, they would not have the resources to defend the country. 

The four-star service chiefs testified at a Senate Armed Services hearing on Thursday at Capitol Hill that under fiscal pressure, they have been prioritizing ready units over modernization. The instability, exemplified by the ritual of year-end continuing resolutions, leads to waste, they said.

"Eight years of continuing resolutions, including a year of sequestration, has built additional cost and time into everything we do," Chief of Naval Operations Adm. John Richardson said. "The services are essentially operating in three fiscal quarters a year now. Nobody plans anything important in the first quarter."

If faced with two major conflicts at once, as outlined by the current military guidance, the US would win, but face high risk, the officials said.

"The only thing more expensive than deterrence is fighting a war, and the only thing more expensive than fighting a war is losing a war," Army Chief of Staff Gen. Mark Milley said.

The service chiefs affirmed that they are against an option being floated in the House for Congress to pass a long-term continuing resolution, as well as the House-passed defense policy bill's plan to shift $18 billion in emergency funding for base budget needs. 

Lawmakers were largely solicitous, saying the myriad threats the US faces should spur Congress to unshackle the military from the the caps dictated under the 5-year-old Budget Control Act.

"Our preference is stable and long-term funding," Milley told Sen. Lindsey Graham, R-S.C., who fired off a leading line of questions on the matter.

SASC Chairman John McCain, R-Ariz., said that with the Budget Control Act, Congress "lied to the American people" because the law failed to reduce the national debt. The military, he said, is "becoming effectively hollow against great-power competitors."

There are five more years of caps, McCain warned, noting a $100 billion mismatch between budget cap levels and the Pentagon's five-year defense plan, and $30 billion of base requirements buried in the emergency operations account. By his calculations, the country must come up with $250 billion more for defense to meet its current strategy.

"Put simply, we have no plan to pay for what our Department of Defense is doing right now, even as most of us agree that what we are doing at present is not sufficient for what we really need," McCain said.

The Army is challenged to sustain its counterinsurgency and counterterrorism missions and rebuild its capability against near-peer great power threats. Uncertainty has driven the Army to prioritize readiness in the 2016 defense policy bill, as it will continue to do, over modernization, end strength and infrastructure.

"In other words, we're mortgaging future readiness for current readiness," Milley said.

The Army asked for continued support for modernization in key areas, including aviation, command-and-control networks, and integrated air and missile defense.

The Navy faces a "triple whammy," Richardson said: the high demand of naval platforms and personnel, years of budget uncertainty and the budget levels of the Budget Control Act. The service has largely curtailed modernization as a result.

Continuing resolutions, Richardson said, undermine the trust and confidence suppliers have in the Navy and hinders it from making cost-efficient block buys of parts and supplies.

The Marine Corps this year had its largest unfunded priority list ever, at $2.6 billion. At the same time, "The Marine Corps is as busy as at the height of recent wars," Commandant of the Marine Corps Gen. Robert Neller said.

The Marine Corps needs 38 amphibious warships with an availability of 90 percent to support two Marine expeditionary brigades and provide for its forcible entry mission. It will have 34 by 2022 under its long-range ship strategy.

Neller said the right combination would include 12 big-deck amphibious ships, 12 LPD-class vessels, 12 comparable hull forms and two LHA(R) America-class amphibious assault ships, and "others."

The Air Force bought about 175 fewer fighter aircraft than it did 25 years ago, though it remains committed to its top three conventional acquisition priorities, the F-35A Joint Strike Fighter, the KC-46A Pegasus and the B-21 long-range bomber, said Air Force Chief of Staff Gen. David Goldfein.

The 2017 budget also requests recapitalizing its bomber fleet, including the B-21, replacing the Air-Launched Cruise Missile with the Long Range Standoff Weapon — a program with some Capitol Hill pushback.

The budget instability, Goldfein said, prevents the Air Force from replacing aging airframes, expanding the cost of maintenance exponentially.

The industrial base too suffers when demand is unpredictable, and companies have had to lay off their technical workforces.

"Everything we deal with in terms of unstable budgets, they deal with as well," Goldfein said.