In a week the Senate prepares to vote on the second, and final, of the Panama Canal treaties. The canal has stirred more words and less passion than any supposed major issue in memory. Most senators, and Americans undoubtedly want to be done with it. Certainly there are more critical questions. It's hardly surprising that passage of the second treaty was assured - until, that, is the last few days.

Now, we're told, the treaty package is in jeopardy. The problem, it's being said in Washington, lies with the Panamanians. At the last moment they are letting their concerns be known and raising the prospect that they may reject the treaties as amended ratified by the Americans. Howard Baker, leader of the Republican pro-treaty forces in the Senate, has bluntly warned the Panamanians to cool it, or risk losing all.

"Any rocking of the boat," Baker said, "could put these treaties in extreme peril." If the Senate gets the idea Panama is dissatisfied, or if any action occurs either in street demonstrations or in protests at the United Nations - well, there goes the deal.

Spoken, appropriately, like a big brother to a wayward sibling. Keep quiet and smile, or else.

There is a problem with the treaties, but it doesn't lie with the Panamians. As presently amended, the first of the treaties represents a negation of almost 50 years of bipartisan American foreign policy. It puts us back in the business of nakedly advocating intervention in the internal affairs of other nations, something history and a host of documents we've legally subscribed to presumably put to rest long ago.

Not that American practices has always lived up to American ideals. At times we have violated our own oths and attempted to overthrow or subvert other Latin nations - Guatemala in the 1950s, the Bay of Pigs in the 1960s, Chile in the 1970s all are part of broken U.S. promises. But in each case our secret interventions caused serious international problems for America, contributing to a tarnishing of the U.S. reputation for good faith abroad and to a lessening of belief in the government at home. Today, particularly, in the post-Vietnam, post-imperialist America when we are preaching the cause of human rights of emerging nations, a U.S. endorsement of the principle of armed intervention defics belief.

This is an offensive doctrine. It will be a tragedy if allowed to stand. The test lies not with little Panama, but with us. It's not too much to suggest that American principles are on trial here, and that the Senate still can redeem them. The question is whether we act like a great power, assured of our strength and confident in our convictions, or like a petty, churslish state - whether, in short, we up-hold what we have pledged to unhold.

And there the record of history is clear.

Franklin Roosevelt gets credit for reversing the old Yankee imperalist, Colossus of the North Jungoist stance toward Latin America. The second Roosevelt upending the interventionist policies of the first: It made for instant political mythology.

In fact, FDR's "good neighbor" ploicy did mark a new era in Latin American relations. That first year of his presidency he dispatched a U.S. delegation to an International Conference of American States meeting at Montevideo. Out of that came a formal document on "The Rights and Duties of States" which the United States signed. Article 8 declared: "No state has the right to intervene in the internal or external affairs of another."

It was a sweeping renunication of the right of intervention that had been troubling the hemisphere during the era of gunboat diplomacy and the dispatching of the Marines to protect our interests - mainly private investments - for so many years.

But the truth is it was Roosevelt's predecessor, the historically unlucky Herbert Hoover, who should get the praise for putting America on a different course toward its neighbors. Until Hoover's presidency, American policy was militaristic and arrogant: we did what we pleased, whenever and however we wished.

Hoover changed that. Not long after taking office he stated flatly that it "ought to be be the policy of the United States to intervene by force to secure or maintain contracts between our citizens and foreign states or their citizens." Inother words, he promised never to intervene to protect pressures of the Depression, when debts were repudiated throughtout Latin America, he never wavered in his resolve.

His Republican administration had made possible the acceptance of FDR's further pledges and policies.

From that point on, the United States repeatly reiterated its approval of the principle of nonintervention. Roosevelt traveled to a celebrated Buenos Aires conference in 1936 at which a new treaty strengthing the pledge not to intervene "directly or indirectly" was signed by 22 nations, including the United States.

Over the decades those principles have been reaffirmed, legally and in writing again and again by this nation - and not only as regards the hemisphere. In the U.N. charter, in the charter of the Organization of American States, in declarations signed at Chapultepec, Mexico in 1945, in the Treaty of Rio de Janerio after World War II - all these brought fresh United States pledges against intervention.

Not does the record end there. In the Helsinki accords, signed three years ago by President Ford, similar statements received our pledges. When he spoke to the Helsinki conference after signing the documents, Ford said "The United States gladly subscribers to this document because we subscribe to every one of these principles." Non-intervention was first among the basic principles of relations between states he cited. It was followed by, Ford's words, "sovereign equality, self-determination, territorial integrity, involability of frontiers."

That same year a new protocol to the Rio Treaty was signed at San Jose. A new article provided that: "Nothing stipulated in this treaty shall be interpreted as limiting or impairing in any way the principle of nonintervention . . ." And the United States also voted in favor a resolution then which reaffirmed "solemnly the principle of nonintervention."

All in all hardly an amibguous record.

Before the Senate voted on the first Canal treaty last month, the president struck a bargain with a little-known Democratic senator from Arizona. The deal: the senator, Dennis DeConcini, would vote for the treaty if the president would support an amendment DeConcini proposed. Carter agreed, the arrangement was made public.

DeConcini's amendment, which the Senate adopted, gives the United States the unilteral and perpetual right to intervene in Panama militarily of the canal is closed or its operations are in any interfered with, as defined by the United States. As DeConcini told the Senate:

"There are no conditions, no exceptions, and no limitations on this right. By the terms of the amendment, the United States interprets when such a need exists, and exercises its own judgment as the means necessary to insure that the canal remain open and accessible."

And, his key passage on the use of military force:

"These words are absolutely crucial because they establish the American right . . . to take military action if the case so warrants. It further makes it clear that the United States can take military action on Panamanian soil without the consent of the Panamanian government."

As Sen. Edward M. Kennedy (D-Mass.) said at the time, Panama was being asked "to accept an amendment which has the ring of military interventionism - not just during this century, but for all time."

Whether Panama finally accepts or rejects that outrageous interference in its sovereign affairs is not the point here - although that language clearly holds disturbing implications for all nations with which the United States has relations. The point is whether this country's repeated pledges mean what they say.

It's inconceivable that a single U.S. senator would accept such intrusion in the affairs of his state, by any force, anywhere, anytime. It should also be inconceivable for the Senate to fail to recongnize that this language establishes an unworthy, and unnecessary, principle.