Rep. G.V. (Sonny) Montgomery (D-Miss.), the chairman of the House Veterans' Affairs Committee, is of the old South and the old school of congressional leaders: He hasn't seen a war that the nation should not have won nor a battle that it shouldn't commemorate.

So when Montgomery heard in February about what had happened to a joint U.S.-Philippine memorial to the hundreds who died on the island-fortress of Corregidor during World War II, he was sympathetic. This spring, when he saw what had happened to the battleground, he was outraged.

"It was like letting someone throw paint on the Iwo Jima Memorial or letting a large cross fall down in Arlington Cemetery," Montgomery said in a recent interview.

Vandals have stripped valuable metal off the big guns that had protected the fortress, first from the Japanese in 1942 and then from the returning American forces in 1945.

The jungle has overtaken the ruins of most of the buildings, many of the roads around the base have vanished and many of the tunnels in which Gen. Douglas MacArthur and his command sheltered in 1942 from an intense Japanese bombardment are "unkempt, unlighted and sometimes impassable," according to a congressional report on the visit.

"It was disgusting, a real mess," said Charles E. (Butch) Joeckel Jr., executive director of the Disabled American Veterans. "The pools of water that were supposed to flow around the memorial were stagnant and infested with bugs."

According to the congressional report, "The scenes were of almost total desecration of every aspect of Corregidor's historic sites including the vestiges of battle, the buildings around the memorial and the memorial itself."

That assessment has seemed only to spur Montgomery to action.

What he did on his return to Washington is an example of how a single congressional committee chairman can galvanize attention and force action on an issue that seems far removed from the concerns of the federal bureaucracy.

But then, Montgomery knew what many outside of the nation's capital didn't know: that the government has an agency whose principal concern is maintaining American military cemeteries and battle monuments overseas.

Montgomery turned to the American Battle Monuments Commission, a tiny, independent federal agency with a Washington staff of 11, an annual budget of $12 million and responsibility for 24 overseas cemeteries, 14 memorials and two commemorative tablets.

Actually, officials at the 64-year-old agency, nestled in a carpeted fifth-floor suite amid the Army Corps of Engineers headquarters on Massachusetts Avenue, already knew of the problem. "We got a lot of complaints in here about the American memorial over there," said Col. Frederick C. Badger, one of three retired Army officers who have been recalled to active duty to help run the commission.

But because the Corregidor memorial was established by a joint U.S.-Philippine commission and supposedly maintained by the Philippine government's department of tourism, the U.S. agency has been unable to act.

"There is no question that place is in an awful condition," said Badger, who visited the island after Montgomery. The 11-member board that oversees the commission also was sympathetic.

The problem Badger saw was twofold: money and the Philippine government.

While Montgomery quickly won the promise of $100,000 from the Disabled American Veterans, whose officials accompanied him to the Philippines in April, Badger's review saw the need for much more money.

His estimate calls for $5 million to restore a key portion of the fort and the memorial to a more presentable status, plus $500,000 a year to operate the memorial and a staff of 50 to maintain it.

Just getting the Aquino government, beset by serious economic and political troubles, to consider the issue has not been easy, according to Montgomery. The Corregidor memorial, dedicated by the United States and the Philippines in 1968, simply fell victim to the Marcos government's inability to maintain it.

Corregidor, situated strategically at the entrance to Manila harbor, had briefly been a major tourist attraction, with hydrofoil boats ferrying sightseers from Manila to the fort. But that service collapsed, as did the electric and water service needed to run the U.S.-Philippine memorial atop the 600-foot-high cliffs on the island.

Today the hydrofoils have given way to slower and less crowded tour boats that daily bring a handful of tourists, many of them Japanese, to the battlefield. The island itself is occupied only by a small group of farmers and their goats.

The State Department, at the battle commission's urging, has opened talks with the Aquino government about the memorial. "They are receptive, at least they are not throwing up any roadblocks," said Badger.

The talks thus far have focused on the government's desire to open up the island, about an hour's boat ride from Manila, to development. "We would like to develop it, but we don't want anything like Disneyland there," said the colonel.

The Philippine plan calls for opening up the east end of the island to a resort-style development with hotels, shops and other attractions and reopening an old street car service to link that area with the "Topside," the western end of the island where the memorial is.

The idea of trolleys running through that area troubles the American commission, which would like to see any tourism district clearly separated from the memorial area. The Americans would like the area restored to the condition it was during its famous four-month-long siege by the Japanese.

The battle commission, which President Jimmy Carter once targeted for abolition and then was astonished to see how many friends it had, is prepared to run the Corregidor memorial if Congress concurs.

It did the same in Europe recently, taking over a small memorial at Pointe du Hoc in Normandy after the French government declared it was unable to care for the site where American Rangers in June 1944 scaled a 100-foot-cliff overlooking Omaha Beach.

But the commission, which prides itself on maintaining its sites with "not a blade out of place," as the operations director, Col. William E. Ryan Jr., puts it, has not had much luck in obtaining tax money for new projects.

It currently lists 25 World War II battles that it proposes to commemorate, but Ryan and Badger say they have little hope of Congress providing funds for any of them because of concern over budget deficits.

The commission's current major project, a Washington memorial to veterans of the Korean war, was approved by Congress last year but with the proviso that the funds for the $5.5 million monument come from the public. The commission's first fund-raising effort has not met with much success, Ryan said.

A letter to the Washington area's top 100 firms produced $700, and one to the nation's leading unions did only slightly better, raising $2,100.

The sole major success was the Hyundai Motor Corp., a South Korean automobile maker, and its American dealers. They have pledged $1.2 million toward the memorial.

If the commission manages to raise the funds, it would become its second Washington memorial. It built the monument to the World War I leader, Gen. John J. Pershing, who was the commission's first chairman, at 14th Street and Pennsylvania Avenue NW.

When might the Corregidor battlefield join the list?

"Well," said Ryan with a deep sigh. "It isn't in our 1988 budget and it isn't in our 1989."

The answer, officials said, will probably depend, as the whole Corregidor issue has, on Montgomery's clout on Capitol Hill.

"He's the sparkplug," said Badger.