One of the least vulnerable liberal Republicans in the East is the Attorney General of Massachusetts. It is a safe prediction to say that Edward W. Brooke will be re-elected by a wide margin to the post he won two years ago, regardless of the expected Johnson landslide.

But Brooke is less confident than his partisans or the experts are, and he insists upon "running hard and scared until the end of the campaign," in order to achieve the largest possible mandate for the continuation of his reform of Massachusetts law and politics.

In an office which might easily be a center for the famed corruption of Massachusetts politics, Brooke has endeavored to make his own name synonymous with the "rehabilitation" of state governmental practices. He has pushed the Crime Commission through an endless series of indictments of public officials, most of which have resulted in convictions; has prosecuted offenders in the Boston Common Garage scandal; and has taken steps to submit Massachusetts' "authorities" to more thorough public scrutiny. Brooke earned considerable statewide popularity with firm policies to limit abuse of public land condemnation procedures.

In controversial "explanatory opinions" he forcefully supported the U.S. Supreme Court's school prayer decision, and he spoke out in a personally difficult situation against last year's boycott of the Boston schools due to de facto segregation. While adopting the politically safe course of not passing judgment on the racial balance of the schools, he ruled that children's parents were responsible for their attendance under any circumstances.

He has had his problems, too, as his opponent in this election, State Senator James W. Hennigan, has been quick to point out. ("Brooke has been more interested in headlines than real performance," Hennigan charges.) This fall strong charges of partisanship in Crime Commission affairs were levelled, after the indictment of former Governor Foster Furcolo. Last week, Furcolo charged that Commission chairman Alfred A. Gardener had violated an old "Corrupt Practices Act" that forbids gifts from state office holders to political candidates. Brooke has attempted to clear himself by pointing in another "explanatory opinion," to the fact that Gardener's $100 contributions was to the Brooke campaign committee and not a personal gift.

If there is any measure of public suspicion of Brooke, it is certainly not obvious when he campaigns. As perhaps the most prominent Negro state office holder in the nation, he employs a campaign technique that bears strong resemblance to the Kennedy style of politicking. He moves about with incredible speed, always shaking hands, always smiling broadly, and never showing the irritation that most campaigners feel and many display. As he rides along in his car, he invariably stops at street corners for brief hand-shaking sessions, and he shouts greetings from his car window to cab drivers and motorcyclists who pull alongside.

Brooke is relaxed and unruffled on a vote-getting stint, and he strolls into a cafeteria full of people as if he were about to sit down and do a day's office work right there in the middle of it all. He literally runs from one table to another and grabs every hand in sight.

At the John Hancock Insurance Company in Boston this week Brooke was a smashing success. Tables of girls in the cafeteria giggled as he approached, and many men stood from their lunches to shake his hand. (When gubernatorial candidate Francis X. Bellotti put in a similar appearance in the cafeteria, the John Hancock officials observed, this did not happen.) In a typical interchange there, he approached a table of women and said, "I'm Ed Brooke. Sorry to disturb your lunch, but I just wanted to say hello." As he left the table, one woman turned to another and signed, "Such a nice smile. I think I'll voter for him." Later, when a woman reprimanded that he had already shaken her hand (this is uncommon for his astute "campaign memory") he retorted that he "just wanted to come back for seconds."

Brooke, now 46, will probably have a promising political destiny in Massachusetts, and perhaps national, politics if he is re-elected this year. A Scranton supporter at the Republican Convention in July, he speaks of the G.O.P.'s future with great concern. The Goldwater candidacy, he insists, "is incompatible with basic American principles," and he has given the national ticket a totally cold shoulder. While he will not hazard a prediction of the outcome of the Presidential election, he insists that "if Goldwater and Miller are defeated overwhelmingly, it is unquestionable that the liberals and moderates must assume party leadership."