I believe the techniques used to exploit the issue of the Panama canal treaties are the most compelling evidence to date that an ominous change is taking place in the very character and direction of American politics.

In his farewell broadcast several months ago, Eric Sevareid warned of the paradoxical rise of "dangerously passionate certainties" in a time of no easy answers. One could speculate endlessly about the root cause of this development: a generation of disillusion and disenchantment with the lack of integrity and the misuse of power of leaders and institutions; the humbling experience in Vietnam; the unrelenting pressure of unfocused anxieties about national direction and purpose; and the all-too-human inclination to turn in frustration to the slogans and nostrums of a simpler time. But whatever the cause, I see abundant evidence that these "dangerously passionate certainties" are being cynically fomented, manipulated and targeted in ways that threaten amity, unity and the purposeful course of government in order to advance a radical ideology that is alien to mainstream political thought.

Already we have seen the vigor of the two-party system sapped by this phenomenon. More and more Americans appear unwilling to abide by the essential ethic of the party system -- that willingness to tolerate differing views within the party, and to accept the party platform, however unpalatable some of its provisions, in order to advance a general political philosophy. As a result, the traditional role of the parties is slowly being usurped by a thousand and one passionately committed special-interest, splinter-faction and single-issue constituencies.

I believe in firm and outspoken commitment to principles and convictions. I would readily agree, as someone once said, that there are times when compromise offers little more than an "easy refuge for the irresolute spirit." But I would make a distinction between commitment that is rooted in reality -- commitment, for example, that recognizes the linkage between problems and the consequences of ignoring that linkage when applying solutions --and commitment that denies reality and is, in truth, but the blind and obsessive pursuit of illusion.

Extremists who deny reality in the pursuit of illusion deny something else, something of fundamental importance in our republic of free men and women. They deny the differences that distinguish one human being from another. They deny the indisputable fact that each of us is the result of a unique combination of genes and chromosomes, of influence and impressions, of training and of faith, and of the milieu from which we sprang. In short, they deny everything that science and simple observation tell us about human nature and individual capacities and limitations.

By proceeding from the flawed premise that all of us are alike, it is easy for ideologues to conclude that we must see every issue as they see it --in our motivation. And they proceed from that premise with an arrogance born of the conviction that they and they alone have a corner on patriotism, morality and God's own truths, that their values and standards and viewpoints are so unassailable they justify amy means, however coarse and brutish, of imposing them on others.

I want to be fair about this. In the particular instance of the canal treaties, I'm talking about the kind of politics practiced by what has come to be known as the New Right. But I want to note that the record of extremists on the ideological left bears a remarkable, and regrettable, similarity. . . .

There have been times when some of us have felt the wrath of the purist left. And now -- today -- many of us are feeling the wrath of the New Right because we will not bow to their threats and vote against ratification of the canal treaties.

Indeed, one element of the New Right -- the Conservative Caucus --did not wait for me to announce how I would vote on the treaties. They launched their attack months ago.

Last summer the national director of the Conservative Caucus, Howard Phillips, said conservatives should make "a political sitting duck" of Tom McIntyre over the canal treaties, and the Conservative Caucus could "make it a political impossibility for McIntyre to vote for that treaty."

On Dec. 4, 1977, the Conservative Caucus of New Hampshire passed a resolution of censure and served it on me like a subpoena. I was "censured" for a speech i made last September, a speech in which I took neither side on the treaty issue. . . . but merely spelled out the pro and con arguments I would have to consider when I made my decision on how to vote. .Not only did the resolution censure me, it "required" me to appear before the Caucus in Wolfeboro, N.H., on Feb. 12 to justify why I should not vote against ratifcation and or refute said censure. . . . Wll, I did not go before the Caucus, so I have to assume I was tried in absentia and found guilty of a decision I had not yet made. . .

Hear the revealing words of Howard Phillips on other occasions: "We organize discontent . . ." he said. "We must prove our ability to get revenge on people who go against us. . . . We'll be after them, if they vote the wrong way. We're not going to stop after the vote's past."

And hear the words of another spokesman for the New Right, Paul Weyrich, director of the Committee for the Survival of a Free Congress: "We are different from previous generations of conservatives. We are no longer working to preserve the status quo. We are radicals, working to overturn the present power structure of this country."

These people are different from traditional conservatives. I know the traditional conservatives of my own state. I have competed with them in the policical arena. I have worked with them in behalf of our state. They are people of honor, civility and decency.

The New Right cannot comprehend how people of opposing viewpoints can find common ground and work together. For them, there is no common ground. And this, in my judgment, is the best indication of what they truly are -- radicals whose aim is not to compete with honor and decency, not to compromise when necessary to advance the common good, but to annihilate those they see as "enemies."

And if "conservative" in the title "Conservative Caucus" is an ironic misuse of the word, it is doubly ironic that destiny would link the national chairman of the Conservative Caucus -- the governor of New Hampshire -- with William Loeb, the publisher of New Hampshire's largest newspaper and the master practitioner of the politics of threat and vengeance. .In all of this nation, there may not be two more recklessly belligerent public figures than Meldrim Thomson and William Loeb. .I am certainly not sanguine about such powerful and ruthless opposition, but after 16 years of weathering the sustained attacks of Mr. Loeb and his ilk neither am I anguishing over the outcome. . .

[But] my political fate is not my concern here today. My concern is the desperate need for people of conscience and good will to stand up and face down the bully boys of the radical New Right before the politics of intimidation does to America what it has tried to do to New Hampshire.

So I say to my colleagues:

If you want to see the reputations of decent people sullied, stand aside and be silent.

If you want to see people of dignity, integrity and self-respect refuse to seek public office for fear of what might be conjured or dredged up to attack them or their families, stand aside and be silent.

If you want to see confidential files rifled, informants solicited, universities harassed, "enemy hit lists" drawn up, stand aside and be silent.

On two occasions in the past several years, we witnessed dramatic evidence that the American people desperately want to put acrimony and division aside, to heal the wounds, and to come together again as a people.

The first was the brief and shining moment on Independence Day of our Bicentennial celebration, a moment when all at once we were again united in the pride of our heritage, our esteem and affection for one another, our confidence in the future.

The second occurred but a few short weeks ago when the entire nation paused to pay its final respects to that most beloved of Americans, Hubert Humphrey.

In the long run, I am confident that the forces of decency and civility will prevail over the politics of threat and intimidation, just as I am confident that reason and commitment rooted in reality will prevail over extremism in the pursuit of illusion.

But if that does not occur in time to save the treaties -- or those of us who support them -- then I, for one, will go home to Laconia, N.H., sad to leave this office, but content in heart that I voted in what I truly believed were the best interests of my country. CAPTION: Picture, "In all this nation, there may not be two more reckless belligerent public figures than [New Hampshire Gov.] Meldrim Thomson and [publisher of the state's largest newspaper] William Loeb."