When Gen. James L. Jones leaves his post as commandant of the Marine Corps early next year to become the top U.S. military officer in Europe, he will become the first Marine chief who instead of retiring moves on to another top slot in the armed forces.

That radical departure from past practice "means evidence of increased acceptance that Marines can do a lot of different assignments," he said in an interview at his Pentagon office last week. He noted that his selection as the supreme allied commander, Europe -- where he will be the first Marine ever to hold that job -- follows the appointment of another Marine general, Peter Pace, last year to become the first Marine to be vice chairman -- or chairman -- of the Joint Chiefs of Staff.

Reviewing his three years as commandant, Jones also discussed:

* The new Marine deployment in the Horn of Africa.

* The health of the Marine Corps.

* The state of the troubled V-22 Osprey aircraft program.

* His unhappiness with certain aspects of being a service chief in today's Pentagon.

Discussing U.S. military activities against terrorism in Africa, he said that well into next year, Marines will be a major part of a new counter-terrorism operation called "Joint Task Force Horn of Africa" that is based in Djibouti and on Navy ships in the Red Sea. The task force is focusing on preventing the al Qaeda terrorist network from finding new havens in Somalia, Yemen and elsewhere in the region.

Some Special Operations troops and perhaps some "civilians" -- which is usually Pentagonese for CIA operatives -- also will be assigned to the task force, he said. The chief of the operation is Marine Maj. Gen. John F. Sattler, the commanding general of the 2nd Marine Division, based at Camp Lejeune, N.C. (The other big Marine division, the 1st, based at Camp Pendleton, Calif., is the Marine unit on tap for any U.S. attack on Iraq, Pentagon officials have said.)

In the past, that new task force might have been peopled only by Special Operations troops. But those forces are being kept so busy by the global war on terrorism that the Pentagon is looking for ways to have the Marines and other conventional forces take on more of that sort of work. Jones said the Marines are prepared to execute the more basic Special Operations missions, such as searching and seizing ships, rescuing downed pilots and conducting reconnaissance operations.

The Marines expect to operate more closely with Special Operations troops in the future, he said. But he also warned that "there's a lot of culture to be overcome here," with "some natural resistance to change" in both the Marines and in the Special Operations community.

On the health of the Corps, Jones said the best measure of the condition of a service is whether its members want to stay in -- a trend that is quantified as "retention." He noted there is now an 18-year high in officer retention in the Marine Corps. (In the current year, 7.2 percent of Marine officers will leave the Corps, compared with a historical rate of about 9.3 percent, a Marine officer said.)

Jones also said he is proud that in speeches to classes at Quantico over the last three years, he has been able to speak to "every lieutenant in the United States Marine Corps -- not as a graduation speaker, not as a bouquet thrower, but real in-depth, 'This is what you signed up for, this is what we expect of you.' "

His major regret, he said, is that he hasn't been able to do more to reform the way the Pentagon buys its equipment. "The one thing that I wish I could have been more influential on is business and acquisition reform," he said.

Jones's biggest acquisition nightmare has been the V-22 Osprey program, which at one point threatened to overwhelm his term as commandant, with 23 Marines killed in two crashes in 2000.

Although he said he leaves the job "optimistic" about the V-22, he conceded that senior civilian Defense Department leaders, including Pentagon acquisition czar Edward C. "Pete" Aldridge Jr., remain skeptical of the program to build the aircraft, which takes off and lands like a helicopter but tilts its rotors forward in horizontal flight.

He believes, however, that a series of flight tests over the next year should clear up their concerns. For example, some officials doubt whether the aircraft -- which has rotors on its wings rather than directly above its body, as with helicopters -- can safely land on the deck of a ship while fully loaded and with one rotor over the water while the other is over the deck. "We have front-loaded the testing program so that those issues will be addressed," he said.

At the same time, he said he is "resisting" talk of accelerating the testing program. "I wouldn't want to see us rush it too fast and get back to the bad old days that we've just come through," he said.

Jones said he remains troubled by legal restrictions on service chiefs that limit their ability to intervene in weapons acquisition programs. Under the law, the acquisition chiefs in each service report not to their service chief but to the civilian undersecretary of defense for acquisition.

"I don't mind being held accountable for acquisition failures," he said, "but it seems odd to me that the law specifically says I don't have anything to do with that."

Being a chief became much more fulfilling after Sept. 11, 2001, Jones said, when the Joint Chiefs really began working as a body to support the global war on terrorism.

"I've enjoyed the relationship . . . much more since 9/11, because of the fact that there is a focus now on making sure that we're all in this together," Jones said. "That level of dialogue," with the service chiefs studying U.S. war plans, "frankly was missing for a long time."

Marine Corps Commandant James L. Jones will become supreme allied commander, Europe, early next year, the first Marine to hold that job.