MANCHESTER, N.H., March 10--With the primary campaign here drawing to a close, President Johnson's chief supporter, Governor John King, has taken off the gloves.

A series of radio and newspaper advertisements sponsored by the Democratic State Committee, warned voters that "the Communists in Vietnam are watching the New Hampshire primary." Broadcast four times an hour on radio stations across the state, they caution against voting "for fuzzy thinking and surrender." On Friday, Governor King charged that a good showing by McCarthy would be "greeted with cheers in Hanoi."

It is not certain what effect these tactics will have on the voters Tuesday. McCarthy and his supporters are hoping a backlash of resentment against the charges will work in their favor, just as the Johnson pledge card effort had done at the beginning of the campaign.

By week's end, such a backlash had begun, at least among party officials. Candidates for five delegate slots, who support President Johnson, issued a statement Friday repudiating the advertisements. Senator Tom McIntyre (D.N.H.), who has also been a chief Johnson backer, disassociated himself from the King statements.

"I think you do him [McCarthy] a very great injustice to say this because his patriotism, his loyalty to this country, is as good as yours or mine any day of the week," King told a Clairemont radio station.

Senator Robert Kennedy (D.N.Y.), issued a statement that he deeply regretted the attacks. He noted that "the same king of charges were made in 1960 against President Kennedy, and the present charges are as baseless now as those were then."

In a statement today, McCarthy charged that "supporters of the President have failed to defend the merits of his policies or discuss a single one of the great issues which confront this country... The entire campaign for the President has consisted of a single shrill and irrelevant and false note; the implication that opposition to the President's policies is somehow disloyal."