Helped by high unemployment and a perceived return of patriotism, the armed services so far have been able to meet or exceed their recruiting goals during President Reagan's tenure. They've even had to turn away some aspiring soldiers, sailors, airmen, and marines.
But now that the economy is improving and unemployment is dropping (and the rush to sign up after the Grenada invasion has subsided), the first signs of potential trouble ahead have been spotted.
Recruiters are reporting a sharp drop in the number of young people coming into recruiting offices to find out about life in uniform. This is especially true for the Army, which has traditionally found it more difficult than the other services to attract recruits.
For the first quarter of the current fiscal year (October-December 1983), Army recruiters recently reported 22 percent less interest in joining up (as measured by those taking the basic qualification test) than the same period a year earlier.
''Is this dangerous? If we're still meeting our (recruiting) goals, the answer is no,'' says an Army spokesman, Maj. Robert Mirelson. ''But down the line, it may be.''
In annual reports to Congress, military officials also are warning that a healthier economy, plus the projected 15 percent drop in young people reaching military age due to the wane in the baby boom, could make it harder to fill the ranks.
''Competition for our nation's talented high school graduates is tough,'' Army Assistant Secretary Delbert L. Spurlock Jr. told a congressional panel last week. ''This makes recruiting extremely difficult. The upturn in the economy and the shrinking pool of 17- to 21-year-old males will make the competition even keener.''
With many new and technically complex weapons entering the United States arsenal, quality of military personnel is seen as particularly important. According to most recent figures, 94 percent of new recruits are high school graduates, compared with 75 percent of those eligible.
But according to senior officers, even under the best of circumstances, first-term recruits with higher test scores are less likely to stay in uniform than those who are less capable. And that spread is expected to widen as better civilian jobs become available.
''In 1983, we had a very large number in the reenlistment pool with a high propensity to stay,'' says Lt. Gen. Robert M. Elton, Army deputy chief of staff for personnel. ''But in fiscal year 1985, the situation will be reversed. The pool of first-term eligibles will be smaller . . . and the propensity to reenlist will be lower.''
In some areas, this is also true of officers. The Navy, for example, has 26 percent fewer nuclear-qualified officers than it needs, a shortfall projected to reach 33 percent by 1989.
''The recruiting and retention environment . . . appears to be changing in ways which will make it increasingly more difficult to continue meeting our manpower requirements,'' says the Navy's personnel chief, Vice-Adm. William P. Lawrence.
There are different ideas about how this challenge sould be met.
The Reagan administration - which last year sought a military pay freeze - now wants a salary hike for all military personnel. It also favors selective reenlistment bonuses and education programs to keep the most valued uniformed personnel aboard.
Congress is pushing two issues that are always politically popular: a new GI Bill that would benefit all in uniform, and greater emphasis on reserve and national guard units.
Congress has directed the administration to name a new assistant secretary of defense for reserve affairs, and the nominee is expected to be Vietnam war hero and author James Webb.
The administration says it believes (and has scientific data to back up its assertion) that a new GI Bill would not be cost-effective despite its political attraction. While some lawmakers think it should be doing more, the administration is beefing up the reserves and National Guard. Assistant Defense Secretary Lawrence Korb said the other day that Army guard and reserve forces would outnumber those on active duty by 1990.
Rep. Les Aspin (D) of Wisconsin, chairman of the House Armed Services personnel subcommittee, says the military also should be recruiting more women. This could be particularly true of the Air Force, he said, where women are eligible for 93 percent of all enlisted jobs (those not subject to the combat exclusion) but comprise only 11 percent of the force. Since the draft ended a decade ago, the number of women in uniformed service has quadrupled to about 200 ,000.
In a recent report, Representative Aspin suggested that the service secretaries consider doubling the proportion of women in uniform (now about 10 percent for all services) over the next five years.
''While we are looking hard for men to fill the ranks,'' Aspin says, ''there are women out there - high-quality women - eager to serve.''