DENVER-It rankles Senator George McGovern that the widely accepted knock on him as a political leader is that he does not charge up the voters to shrieks of enthusiasm. "No charisma," political buffs are apt to say, when discussing the man who evoked the biggest popular response of the 1968 Democratic convention, for his rousing performance in the candidates' debate before the California delegation.

The South Dakota Senator is personally mild, all right, tends to speak in complete sentences and simple words, leaves the rostrum before him mostly unpounded, and believes-as he said here last week-that "the task of political leadership is to appeal to what is best in each one of us instead of what is mean and divisive." Yet, anyone who heard him the night before at a raucous Democratic party rally in the municipal auditorium at Albuquerque might be forced to revise his opinion about George McGovern's stump style-and the political atmosphere of 1970.

This was an authentic affair of the old politics-one that featured a candidate for Lieutenant Governor who broke into Spanish song. Senator Bob Byrd of West Virginia describing Senator Joe Montoya of New Mexico as "a pearl of great price in a chalice of silver." and Representative Carl Albert of Oklahoma promising that when he becomes Speaker of the House next year, New Mexico's Congressmen-if Democrats, which they are not now-would surely get committee assignments "that will enable them best to use their talents in the interests of your state."

Mr. McGovern was restrained, in contrast. But when, without a single reference to the Depression, the New Deal or F.D.R., he reeled off a long list of the ills besetting the nation ("in all the states of the United States there are undernourished men and women and boys and girls") and concluded with the Kennedy-like assertion that therefore "the business of this country is unfinished," the rafters rang more loudly than they had for any of Senator Byrd's polyloquence. And so they did again when Mr. McGovern asked acidly of President Nixon's veto of the education bill, "if it's inflationary to invest dollars in young minds, why then is it not inflationary to build an antiballistic missile system we do not need?"

The Senator wound up, to a thunderous ovation, with the kind of assertion Mr. Nixon and Mr. Agnew have rendered most candidates of both parties too frightened to make. The Democrats, he said, ought to be pledged "not to fear and intimidation but to the blessings of liberty."

In fact, in two days of campaigning in New Mexico and Colorado, George McGovern broke every rule in the 1970 book of political pusillanimity. For instance:

On liberals: They have their sins to answer for, but are also responsible for many good works-Social Security and antipoverty programs, among others.

On the Middle East: Mr. Nixon's policy is "pretty good."

On young people: He finds them neither violent nor disillusioned this fall but in "a serious and reflective mood" about "the painful gap between what we say we stand for and the things we do."

On crime: The D.C. crime bill, in particular, "violates both the spirit and the letter of due process;" while "liberal Democrats are too quick to panic on that issue and move on to Agnew's ground."

On violence: If the nation would address itself constructively to the problems of war, poverty and injustice, it would see "a dramatic drop in crime and disorder."

On Agnew: "With his radical rhetoric on the right he is a good ally of the bomb-throwers on the left," but the Vice President is still "the Charlie McCarthy in this operation. Let's go after the Edgar Bergen."

On why he didn't sign a protest against the pornography report: "I'm not going to vote against something I haven't read."

Everywhere he goes-about 25 states this fall-Mr. McGovern is meeting with former supporters of Robert Kennedy and Eugene McCarthy and any other Democrat who will listen. He is telling them he is interested in running for President and will make an announcement about it soon after the 1970 elections. He is saying Mr. Nixon can be beaten in 1972, but that the Democratic nominee can only emerge from state primary battles, and so the field is wide open; stay uncommitted for awhile, he advises potential delegates to the next convention.

That is a message not hard to decipher. George McGovern believes that antiwar, new-politics forces that shook the country in 1968 can and will do it again in 1972, and he aims to prove in the primaries that his brand of charisma is good enough to lead the way.