If war were to start Tuesday, Pentagon planners could muster enough rank and experience on Capitol Hill to form a combat unit or man a destroyer. At least 85 members have commissions, many for reserve duty performed in large part since they came to Washington.

The little-known impact of the military in Congress is one reason some people doubt that Congress will ever crack down on retired personnel in government who now draw both pay and pension from Uncle Sam. At least 33 members of Congress receive pensions of as much as $1,000 a month in addition to their $57,500 salaries as active members of the Senate or House.

Government workers and the general public appear divided on the issue of how much, if any, dual compensation is just. Both the retired military and their civilian critics have suggested that Congress is hardly in a position to judge this issue.

Dozens of members of Congress now draw full or partial military pensions in addition to their civilian federal salaries. Others are in retired reserve status and, at age 60, will be eligible to draw military pensions and congressional pay.

Sen. Barry Goldwater (R-Ariz.) is a retired Air Force general who donates his $800 monthly military pension to charity. Rep. John J. Rhodes (R-Ariz.) returns the $510 he receives monthly to the U.S. Treasury to help retire the national debt. Others also may give back or don't keep their military pensions. But spot checks with congressional offices indicate most members keep their pensions, which they of course earned.

The dual compensation law, which governs the money that 141,000 retired military personnel in federal civilian jobs get, was rewritten by Congress a few years back. It gives a big financial break to retired enlisted personnel and reserve officers. Most members of Congress, who have reserve status are officers.

Retired reserve officers and retired enlisted personnel are allowed to keep full military pensions plus full civilian federal salaries. Many of them will receive an estimated 7.02 per cent raise this October as federal civil servants and also a 4.3 per cent cost-of-living raise as retirees. Retired regular officers, by act of Congress, may keep the first $4.045.16 of their military pensions plus half the remainder if they take civil service jobs.

At least two members of Congress, Sen. John Glenn (D-Ohio) and James F. Lloyd (D-Calif.), retired with pay as "regulars" subject to the dual compensation cutoff. Most, if not all, other members of Congress who are retired from the military have reserve commissions, meaning they do or can draw full pensions, when eligible, in addition to full congressional salaries.

Congress has its share of bona fide military heroes. Sen. Daniel K. Inouye (D-Hawaii) lost an arm in combat in Italy. Rep. Olin E. Teague (D-Tex.), Sen. Robert Dole (R-Kan.) and Rep. Bill Nichols (D-Ala.) receive disability payments for war or service-connected wounds or injuries.

But many members of Congress moved up in the military reserve ranks or joined reserve units only after they entered Congress. The Army, Navy and Air Force often have competed with each other to bestow rank on members in hopes of winning congressional favor at budget time. None of the services has been hurt having a key member of Congress in the same uniform at critical times.

Sen. Howard Cannon (D-Nev.) is a retired Air Force general entitled to $1.004.11 in pension money, according to Pentagon records. Cannon chairs the powerful Rules and Administration Committee.

Senate Foreign Relations Committee Chairman John Sparkman (D-Ala.) served in World War I and is a retired Army reserve colonel. His pension entitlement is $258.76, small by Capitol Hill standards.

Rep. Al Ullman (D-Ore.) is a World War II Navy veteran who retired with a pension entitlement of $452.89 per month. He heads the powerful Ways and Means Committee.

Nine House members, who will be 60 years old by 1934, are in the "pending category," meaning they will be eligible for pensions as reserve officers, ranging from captain to general. They are Reps. Tom Bevill (D-Ala.), Jack B. Brooks (D-Tex.), Barber B. Conable Jr. (R-N.Y.), Henry Hyde (R-Ill.), James R. Mann (D-S.C.), Gillespie V. Montgomery (D-Miss.), Carlos J. Moorhead (R-Calif.); John T. Myers (R-Ind.) and James C. Wright Jr. (D-Tex.).

Also eligible soon for pensions as reserve officer retirees are Sen. Charles Mathias (R-Md.) and Sen. Robert Morgan (D-N.C.).

The House is holding hearings on the dual compensation law, and Rep. Robert N. C. Nix (D-Pa.) is expected to propose that future benefits, at least for high-ranking military retirees, be trimmed or eliminated. He may have more trouble in Congress than anywhere else.

According to a 1975 government study, the majority of military retirees in government (93,309 of 141,817 received civilian salaries ranging from $10,000 to $17,999. More than 3,000 earned more than $29,000 in civil service pay and nearly 800 received $36, 000. That still puts the "double-dippers" in civil service jobs well behind their colleagues on Capitol Hill and could put some congressmen in a financial conflict-of-interest situation if double-dipping comes to a vote.