For the U.S. military, the budget outlook seems rather bleak.

We have not yet gotten into the annual rite of spring where senior defense officials trek to Capitol Hill to testify to Congress about the state of their respective services. But news reports on problems with major acquisition programs and force readiness — combined with the usual political posturing over defense spending — lead one to suspect that budget requests of all the services will face intense scrutiny.

The Navy is set to defer the purchase of two amphibious ships. It will also try to cancel the planned refueling of the USS Harry S. Truman, scrapping the nuclear-powered aircraft carrier 25 years early.

The Air Force intends to purchase the F-15X, a modernized version of its 1980s fighter, because its F-35 program is not producing new aircraft quickly enough to offset the loss of older F-15 jets.

As for the Marine Corps, we are already hearing reports — echoing those made repeatedly over the last half-dozen years — regarding the difficulty of maintaining readiness, retaining personnel, and recovering from 18 years of sustained land operations.

Despite the military’s obvious funding needs, the new Democratic leadership in the House is skeptical of increased defense spending — especially in an era of huge federal budget deficits and a total national debt of $22 trillion. As a result, the Pentagon seems unlikely to secure a 2020 baseline budget above $700 billion.

For the Marines, all of this implies that they will need to make some very difficult decisions if they are going to improve the condition of the service. They will have to reconcile the gaps between size, workload, operational focus, acquisition priorities, and the implications of a smaller amphibious fleet.

The Corps’ senior leaders have consistently mentioned the deleterious effects wrought by high operational tempo: stress on Marines and their families; excessive wear and tear on equipment; and the lack of time available for training.

Yet the Corps has been unwilling to increase manpower to ease the operational load on the force, to reduce its operational commitments, or to reduce the number of capabilities it wants to have organic to the Corps. For example, rather than rely on the Navy or U.S. Cyber Command for cyberwar capabilities, the Marines insist on having their own cyberforce.

Unless the Corps makes admittedly hard decisions about size, workload and capabilities, it will continue to be taxed beyond its abilities, and readiness will continue to deteriorate.

For nearly 30 years, the Corps has maintained that future battlefields will require forces able to conduct “distributed operations” in which small, highly capable units are spread across a large area of operations, disrupting enemy access to key terrain or avenues of approach. Yet, it has not changed its forces to align with that concept, nor has it adjusted its acquisition programs or influenced those of the Navy to field new capabilities presumably needed to conduct such operations.

The Marines are not meant to be a supplemental Army. Their unique charge is to project combat power via the sea in amphibious operations that enable a larger naval campaign.

As the Corps assesses budget realities in a world of great power competition, it will have to make some very difficult decisions about how best to use the people and resources it has. It should measure every decision by the extent to which it aligns with the Corps’ primary purpose, codified in law and applied in practice for the past century or more: contributing to the prosecution of a naval campaign.

Whether the Corps’ investment of 3,000 Marines in special operations or 1,000 Marines in a dedicated cyberforce constitutes “best use” should be up for discussion.

Congress will almost certainly be asking these questions, especially if the Corps continues to report that it is operationally stretched beyond its means but does not appear to be changing its habits.