Washington — When Brig. Gen. Peter Dawkins retired from the US Army last week, 20 years before the customary civilian retirment age of 65, there was much comment and concern. Since his days as an outstanding scholar and athlete, then as a combat leader in Vietnam, the young officer had seemed destined for the highest ranks of uniformed service. Other personal reasons were involved in his decision, but being able to draw full military retirement benefits no doubt played a part.
Earlier this year, the Army's chief of staff, Gen. Edward Meyer, also retired - 11 years before a corporation might have offered retirement. A vigorous and youthful man, he had served a full 30 years, beyond which continued service is allowed only in rare cases. Many asked why his talents and experience could not be useful for years to come.
Such cases are part of the growing debate over military retirement, which many critics say is not only too expensive but also forces many valuable men and women out of the armed forces.
''The present system makes retirement the most attractive in the 20-to-22 years of service range, just when experience and expensive military training make perhaps 70 to 90 percent of the personnel the most valuable to the services ,'' said Henry Lawler of the President's Private Sector Survey on Cost Control in testimony on Capitol Hill last week.
It's an issue that has been studied for years. But new congressional investigations have produced data on how to save billions of dollars, and it now seems more likely than ever that reform will occur.
If so, any changes undoubtedly will take into account the special nature of military service and protect those already retired, who are a powerful political force.
Speaking to a House Budget subcommittee recently, retired Chief Master Sgt. Donald Harlow, executive director of the Air Force Sergeants Association, said: ''Overseas service in foreign, remote, and sometimes hostile environments, and abridgment of certain individual rights are but a few of the conditions which set military members apart from society.''
At the least, the defense budget probably will be changed to reflect immediately the long-range cost of military retirement, rather than put this off until the bills come due. This should affect manpower, force structure, and even weapons procurement decisions. For example: Will Congress be as likely to buy two new aircraft carrier battle groups (each of which needs thousands of additional sailors) when it knows that the price will be many millions more because of added retirement costs?
The Reagan administration and the House Armed Services Committee (neither of which would be expected to advocate sharp changes in military retirement) favor this shift to ''accrual accounting.'' Using this technique, the Pentagon's current budget authority would have to include the projected cost of military retirement.
The Congressional Budget Office says this means the administration's proposal to add 180,000 active-duty military personnel would increase retirement costs by
Figuring in future retirement liabilities and the current unfunded liability, the CBO estimates that ''defense budget authority could increase by up to $16.1 billion in fiscal year 1985.''
Such an accounting shift would not change the cost of retirement, just make it more visible sooner. This in turn could be expected to bring about changes in the size and timing of military retirement as many - including some career officers - now advocate.
The chairman of the Joint Chiefs of Staff, Gen. John W. Vessey Jr., has acknowledged that changes in military retirement may be necessary to induce the best career officers and enlisted personnel to remain in uniform more than 20 years.
In a recent article in Armed Forces Journal International magazine, retired Army Col. John Keeley proposes a new retirement system in which the military services would begin retaining some of their career personnel to age 60. Slowing the retirement process somewhat would bring more experience to the armed services, lessen the ''turbulence'' caused by frequent family moves and job changes, as well as save money - as much as $100 million a year, he says.
A new study by the General Accounting Office finds that Uncle Sam's military retirement program is more generous and costly than those of most other countries. Its benefits also exceed those of other state and federal programs, including highly demanding jobs such as air-traffic controllers, Federal Bureau of Investigation agents, and police officers, the GAO reports.
But it is also the concern about keeping the military's best people for longer periods that is driving the new-old debate over military retirement these days.