President Carter's plan to fine tune the $59 billion federal-military pay machine may also make militants out of his 2 million relatively docile office workers. And the compensation changes could give sagging federal unions that badly need an issue a rallying point for recruiting.

The president wants to cut the political lifeline that assures government civilian workers the same annual pay raises as the military.

His plan to link federal pay and fringe benefits to private sector rates may or may not be great for employes and taxpayers. Much depends on the methods used to adjust the system that translates into a $500 million raise for each 1 percent increase.

Key to the pay "reform" is the elimination of the last and most important political crutch government workers have each time a pay raise comes due. It is their link with the military.

The president's pay plan would - if adopted - almost certainly guarantee military personnel bigger annual percentage pay raises than federal employes. Both now get the same amount each October.

Carter's idea is to set federal fringe benefits and pay through a "total compensation" comparison with industry. Since government fringe benefits - like retirement and leave - are generally better than private industry's, the comparison would tend to shave the amount of annual "catch-up" with industry raises.

Under the Carter plan, military benefits would not be counted against the private sector. Armed forces pay raises would continue to be made on the basis of average pay gains in the private sector. Officials say this could give them 3 percent to 5 percent more next year than civil servants would get.

Military leaders have already seized on the pay separation concept. On Thursday - one day after the pay package came out - they proposed that military personnel be exempted from the October 5.5 percent pay raise the president has set for civil servants. Instead they argued that the military - and only the military - get at least 7 percent.

Federal workers have come a long way, considering they have little organized political clout. Most of the pay and fringe benefit improvements government workers have received - most dating from the outset of the Kennedy administration - came with the help of postal unions and their link to the military pay raises.

Eight out of 10 postal workers belong to a union. They can and do get involved in politics. Unions buy tickets to fund raisers, supply bodies where needed, and pay their dues. As a result of the high-esteem postal workers enjoyed on Capitol Hill, white-collar federal workers also moved rapidly up the pay and fringe benefit ladder.

White-collar civil service union leaders have always admitted in private that they rode the backs of the postal workers to higher pay. Whatever sympathy they got on Capitol Hill came because postal people paved the way. Now those days are gone.

Postal workers now bargain independently for pay and fringes. They have moved farther and faster since joining the postal corporation. In their current three-year contract, they get three pay raises, six cost-of-living raises, and lifetime job guarantees.

After losing postal workers as their legislative "shock troops," federal employes still had the military. Evens Sens. Barry Goldwater (R Ariz.) and Strom Thurmond (D-S.C.), unabashed foes of bureaucrats, have voted for federal pay raises. Why? Because the military was linked to them. Many members of Congress and the public felt the same way. Those days may be going.

If Congress permits the pay reforms to become law, white-collar federal workers will be strictly on their own.

They have come a long way without strikes, heavy political involvement or serious militancy. Many consider those roles improper for public employes. But if federal workers lose their military connection, and if they think their pay and retirement are going to be tampered with, then picket lines, protests and politicking may be the way of the future for the bureaucracy.