It is generally believed that it George McGovern is to beat President Nixon next month he will have to win the lion's share of the new south vote.

By coincidence McGovern was in Boston this week for a very such successful rally while a Cambridge Election Commissioner spent part of five days at Harvard registering 150 people. About 50 other students almost all of them undergraduates who were not allowed to register plan to appeal their cases to the tall Board of Elections.

Since Massachusetts is one of the few states that McGovern is confident of winning, it might make more sense strategically for students who support the Democratic candidate to arrange for absentee ballots in their home states. This is especially true if they hail from crucial battlegrounds like New York. New Jersey, Illinois, Ohio and California.

But there is the argument that metropolitan universities are too often isolated from the surrounding community, and the political participation of students might create a closer relationship between Harvard University and Cambridge.

More importantly, the difficulty that some students had in registering here reflects a national issue which has set liberal groups at the throats of local politicians. Is voting a right ordained by the Constitution or a privilege dispensed by the various cities and towns in this country?

The courts have not given a definitive answer to this question, but the most recent decisions have reflected the former view that voting is a fundamental and necessary right in a democratic society.

The McGovern campaign got a big boost this week when the Massachusetts State Labor Council, AHCIO overwhelmingly approved and then gave a standing overtion to a resolution calling for the defeat of President Nixon. Delegates to the state convention meeting in Boston expressed strong support for McGovern in an informal show of hands all this on the heals of an order by George Meany, president of the AFL-CIO that state branches of his grant federation rescind all such "dump Nixon" movements.

McGovern's speech was not as noteworthy for its content--it was basically the same text he has been using around the country for several weeks as for the huge throng of people in Post Office Square who cheered every rhetorical flourish.

Police estimates of the crowd ranged from 75,000 to 100,000--by far the largest rally of McGovern's campaign. The enthusiastic reception stirred the candidate to a bitter denunciation of the Nixon Administration, which he labeled "the biggest moral affront to the standards of our country of any administration in the history of this nation."

McGovern returns on Wednesday for a final boost from the Bay State. Nixon must wonder what Ed Brooke's got that he doesn't have.