For the past 10 years, the United States has engaged in constant warfare. Does that mean the next 10 years will be the same, even after U.S. combat troops are out of Iraq and Afghanistan?

Put it a different way: We have spent trillions of dollars to create the most professional and powerful military force in the world to fight those wars. It continues to cost hundreds of billions more each year to help sustain this all-volunteer force.

But let’s be honest about this. Fewer than 1 percent of the American people have been involved in this constant warfare. As for that spent money, much of it was borrowed, since, for the first time in history, Americans were not asked to pay a tax to support their men and women fighting abroad.

Now the time has come to begin paying that bill, along with other debts caused by ill-constructed national health care, prescription drug and retirement systems that were also put on the government’s credit card.

These issues emerged from a week of reading and listening to news conferences and congressional hearings in which real and potential cuts in defense spending and their future impacts were central issues.

Let’s focus on the impact of the all-volunteer force, not only on the country’s economic problems but also on its foreign policies.

It is already decided that there will be defense spending reductions of some $450 billion over the next 10 years. Part of that will come from reductions in the Army (27,000), with an additional 15,000 coming from the Marines.

The figures to ponder are military personnel costs, including those in active service, the reserves and the National Guard. For fiscal 2001, before the Sept. 11 terrorist attacks, they were $76 billion. The administration-proposed figure for fiscal 2012 is $143 billion. When Congress finishes, it will be less, but not by much.

The Center for Strategic and Budgetary Assessments’ study of the Pentagon’s fiscal 2012 budget concluded: “The base budget now supports a force with essentially the same size, force structure, and capabilities as in FY 2001, but at a 35 percent higher cost. The department is spending more but not getting more.”

As part of its cost studies, the Pentagon is examining personnel expenditures, including military pay, benefits, promotions, recruiting and retention programs, as well as retirement. Officials, from Defense Secretary Leon E. Panetta on down, have said repeatedly that no future changes will affect those currently serving.

“Sustaining the all-volunteer force . . . will be at the heart of whatever we do,” Virginia Penrod, deputy assistant secretary of defense for military personnel policy, told a House Armed Services subcommittee last Tuesday.

A repeated fear is that defense cuts will result in a “hollowing-out of the military.” As best as can be pinned down, that means reductions, whether in numbers or pay, that would leave the services without the experienced noncommissioned and mid-level commissioned officers who actually run things.

As Jo Ann Rooney, principal deputy undersecretary of defense for personnel and readiness, put it last Tuesday before the House subcommittee: “Unlike the private sector, the military services must grow their military workforce internally. It generally takes 15 to 20 years to develop the next generation of infantry battalion commanders and submarine captains.”

The Marine commandant, Gen. James Amos, described what he’s facing during a Council on Foreign Relations meeting Wednesday. There is an eight-month wait for anyone qualified to join the Marines, and a longer wait to be an officer. But he needs new “critical skills” such as counterintelligence, and human and signal intelligence specialists, along with explosive ordnance experts and people for drone operations and cyberwarfare.

And though the overall Corps will shrink from the now planned 202,000 to 186,000 and even lower, he will be increasing Marine Special Forces from 2,600 to 3,600 over the next few years.

In fact that one element of the all-volunteer military keeps growing, with next year’s Special Operations Command budget — around $10.5 billion. There are 60,000 personnel overall and a 7 percent budget increase over fiscal 2011. Its former commander, Adm. Eric T. Olson, told Congress in March “every dollar is necessary to meet the ever-increasing demands placed on our Special Operations forces.”

Those “ever-increasing demands” are what should worry Americans. On Oct. 14, President Obama announced he had sent 100 primarily U.S. Army special forces to Uganda and other Central African countries to assist in a regional military effort to pursue the murderous Lord’s Resistance Army (LRA) and its leader, Joseph Kony. Less publicized was Obama’s reference to a 2010 law Congress passed that called for “political, economic, military and intelligence support for such an effort.”

At a House Foreign Affairs Committee hearing last Tuesday on the anti-LRA deployment, Rep. Edward Royce (R-Calif.), a sponsor of the legislation, said, “This is the reason the U.S. Africa Command was created.” Royce added that since Uganda is helping fight al-Qaeda in Somalia, it was a “fair deal” to help that country defeat the LRA.

The State Department reported that over the past year the United States had provided logistical support and training to regional forces, but that clearly was not enough.

Step back for a moment. A small group of concerned Americans teamed up with members of Congress to pass the bill that authorized the anti-LRA deployment. The Pentagon had prepared specially trained units to carry out what is now designed as a narrowly focused training mission. How many other ungoverned parts of the world exist where leaders can say their enemies represent a terrorist threat and they need U.S. military assistance?

In 1965, President Lyndon B. Johnson sent the 82nd Airborne into the Dominican Republic to prevent what he called a second Cuba. He told Sen. J.W. Fulbright (D-Ark.) that if he hadn’t had the deployment-ready military units, he would have had to rely on diplomacy to solve the problem.

Fulbright later told me that both nations would have been better off had the 82nd Airborne not been there to make the military solution easy when diplomacy appeared more difficult. It’s a lesson remembered and reinforced by the last 10 years of warfare.