Vice President Humphrey's formal entrance Saturday into the Presidential campaign suggested that the old ethnic and regional differences which once plagued the Democratic Party have been replaced by an avant garde form of divisiveness.

Humphrey's announcement seems to have accomplished the once-impossible--it united the wildly disparate interests of John Connally of Texas, George Meany of the AFL-CIO, and Clarence Mitchell of the NAACP. In other words, leaders of Democratic interest groups have reached something of a consensus.

Unfortunately, Humphrey has no guarantee that the followers will tag along with the leaders. In fact, conservative Southerners, union members, and black Americans of all classes--to take three blocs--are likely to split their vote this year without regard to the positions staked out by their leaders. More important, perhaps, it is unclear that the so-called leaders Humphrey has rallied to his banner can be considered political powers any more.

Johnson Administration backers--who have, in large part neatly transferred their allegiance to a logical heir apparent--do not seem to realize that in the last three years, events have caused new cracks in the Democratic Party which Humphrey's pleas for "tolerance, understanding, and mutual trust" cannot paper over.

At this date, the Vietnam war, the rise in urban violence, and Lyndon Johnson's idiosyncratic conduct as President appear to have split the party into three new wings.

One faction is led by Senator Robert F. Kennedy. Its leadership believes in an innovating activist national executive. Although many of its members back the former Attorney General for emotional or ethnic reasons, the Kennedy faction seems committed to unconventional solu- tions to poverty, crime, prejudice, and leftist revolutions abroad. Kennedy's most articulate supporters believe that time has come to move beyond the social palliatives of the past 35 years to insure decent living standards, education, and employment for all citizens. The mood of many Kennedy supporters is characterized by disgust at the sterility of most liberals' response to national crisis and conviction that material and political resources are available to avoid Vietnams at home or abroad.

If most Kennedy people are anxious to get on with their good works, supporters of Senator Eugene McCarthy want to take stock of the individual meaning of political action. What distinguishes many McCarthy backers from those supporting Kennedy is a deep concern over the personal qualities of a President. In fact, the surprising turnout for McCarthy is a reflection of the deep anxiety about the morality of politics that Lyndon Johnson--and apparently Robert Kennedy--have stirred.

McCarthy's attempt to fudge on the specifies of his proposals, and his ability to inspire confidence with soft-spoken wit and snide commentary on other candidates illuminate his psychological strategy. This tack, of course, has the drawback of alienating many black voters. It also confirms the suspicion that McCarthy has too much arrogant cynicism to be an active, imaginative President.

The emergence of the Kennedy iconoclasts and the McCarthy moralists, of course, was probably not possible with-race riots, or a TV in every home. Still, the iconoclasts and moralists easily outnumber the Humphrey wing of the party. This faction seems to be composed, in large part, of older people who have grown comfortable and powerful with the FDR-HST-JFK-LBJ brand of liberalism: give a little to everybody at home and keep the Communists at bay abroad.

What Humphrey and his backers, however, may not realize at this date is that the Democratic Party may pay little heed to its historical successes, fully aware at last that new techniques of political activity and new programs are required. This is not to say that Hubert Humphrey has no chance of getting nominated this August. Kennedy and McCarthy very well might cancel each other out. But even if Humphrey is nominated and elected, he is certain to be the first Democratic President in this century to face strong, incessant, radical uressure from the grass roots and from his former Congressional allies