As hearings go, the one over the proposed Panama Canal treaties has a musty air. Day after day witnesses march through double mahogany doors into the marble chamber, face the glare of the television lights and drone on and on. Old admirals, old generals, old secretaries of state, old labor leaders troop forward before the old chairman.

Sitting in the chair is John Sparkman, who came to Congress from Alabama at the beginning of Franklin Roosevelt's second term 40 years ago. He will be 78 soon. Sparkman blinks into the lights and keeps watch over the time allotted for senatorial questions. That isn't much of a chore: in front of him are three large light bulbs that flash red, green or a cautionary yellow to alert the senators to their time. At one point, as questions cease, Spakman looks around and asks of his colleagues, "Uh, any more?"

Resolution of the main issue rests more on events outside that room that in it. The President has been told, privately, at the White House by leaders of the Senate that there is no way that treaties can be approved without major changes.

Even some of the terms being discussed before the Senate Foreign Relations Committee have an anachronistic ring. Maintaining our maritime position, keeping the sea lanes open, the threat of a monolithic Communist axis, the right of free passage and similar topics stir echoes of the forgotton past.

The other day, as senior retired American military commanders appeared, the discussion ranged back to the turn of the century when Admiral Maham was extolling the necessity for American seapower and our Great White Fleet weighed anchor around the world. And senators and witnesses were recalling the colonial position of the British. "East of Suez," when the Empire ruled supreme. British Raj. America Rex, white man's burden, all stand out as historical curios in this last quarter of the 20th century.

But treaties aside, these hearings are relevant for other reasons, They are demonstrating how dramatically official attitudes have changed in Washington on certain significant questions - and they are showing how weakened the Foreign Relations Committee now appears.

Just a decade ago, before Vietnam ovetook him and the country, Lyndon Johnson was preaching an evangelical brand of patriotism from the White House. "I have seen the glory of art and architecture," he said. "I have seen the sun rise on Mont Blanc. But the most beautiful vision that these eyes ever beheld was the flag of my country in a foreign land."

That kind of jingoistic thinking, backed by the expert opinions of the highest military and diplomatic advisers, carried the American Flag farther than ever before - from Santo Domingo to Saigon and back home, intact but tattered. What strikes the observer about today's hearings over that old symbol of The Flag - the Canal - is the striking absence of those kinds of expressions from the '60 and early '70s.

Even the testimony of Adm. Thomas Moorer, a right-swinger who seemingly would have been comfortable with Custer, failed to set off any sparks. He spoke, as expected, in opposition to the treaties, and for the expected reasons: "do not be surprised, if this treaty is ratified in its present form, to see a Soviet and or Cuban presence quickly established in the country of Panama, Such a presence will seriously complicate the exercise of the claimed 'right' of the United States to intervene."

But he was amiable instead of intense, and his words lacked the type of passion you would have encountered only a few years ago. It was later in his testimony that he expressed a more general concern; but, again, he spoke more in tones of resignation:

"I am seriously concerned about the trends in recent years wherein we have withdrawn from Vietnam, are planning to withdraw from South Korea, have lost considerable influence following the Angola affair, and overall are suffering a gradual change in the perception by the nations of the world of the will and determination of the most powerful democracy in the world."

No senator of either party, no military peer from the immediate past, picked up Moorer's lance.

"I can see how it seems that we are moving step by step back into unhealthy isolation," said Clifford Case, the Republican from New Jersey. But that was symbolic, he suggested: strip it of its symbolism and it was without significance, particularly when applied to the Canal.

"We are now in the midst of a changing climate in a changing world," said John Glenn, the Democrat from Ohio who came to fame as a military office during the Cold War period of intense U.S.-Russian competition and fear. The old "align and live" philosophy was part of the thinking that bound smaller nations to superpowers and led directly to Vietnam, he said.

Now, the great issues revolve around the resources available to a hungry and multiplying world population, the capability of terrorists to wreak international havoc, the transition from a world of surfeit to a world of shortages. They are far removed from the power politics debates that raged so furiously before the Foreign Relations Committee not long ago. But they aren't the only things that have changed. The power and influence of the committee are different, too.

For generations, under such strong chairmen as Clay and Buchanan, Lodge and Borah, the Senate Foreign Relations Committee played a vital part in policymaking. In the modern period, its role became more passive. "Bipartisan" was the byword, but in fact it meant the committee could be counted on to support the President on almost any issue. It's chairmen were old, and loyal.

Tom Connally, the leonine Texan, was 75 when his committee leadership ended. Alexander Wiley was 70 at the end of his tenure. When Walter George succeeded Wiley, he was 77. After George lost his Senate seat, his place as chairman was taken by the venerable Theodroe Francis Green, the oldest person ever to serve in Congress. Green, faltering if not outright senile, was gently forced out by the private pressure of his colleagues when he was 91.

William Fulbright brought a different age - 54 - and conception to his chairmanship. It was under Fulbright that the committee embarked on its period of notable dissent and public controversy. The committee became a forum for debate over was and peace in Vietnam and American purpose around the globe. Now it seems to have stepped back into the shadows.

What the committee provides today is a bland, neutral forum, without sharp focus, without pointed questions, without a sense of clear direction, pro or con, over what remains a truly significant issue. The issue is both old and new. It's over where the Flag flies, why, and for how long.

And over something else: whether we have learned the lessons of our recent imperial past, and whether we should insist the Flag fly in certain places at all.