POLITICS / BILL BRADLEY : N.J. Senator Keeps ‘Em Guessing on Plans for ’92 : But he has indirectly acknowledged he is seeking to position himself for an ultimate White House bid.

Nearly everywhere Bill Bradley went on his rounds recently--at an outdoor rock concert here within sight of the Statue of Liberty, at a high school walkathon in Plainfield, at a poster contest in Piscataway--someone asked him about running for President.

Sometimes the New Jersey Democrat responded with a smile. Sometimes he just shrugged. The most he ever said was: “But I like it in the Senate.”

It is clear that as he launches his heavily favored candidacy for a third Senate term, the 46-year-old Bradley wants to keep everyone guessing about his political future. But it is also clear, as Bradley himself indirectly acknowledged in an interview, that he is working hard to position himself for an ultimate drive for the White House.

That is good news for the many Democrats who for years have been waiting hopefully for the former New York Knicks basketball star and Rhodes scholar to make his bid for the presidency. They reason that with his Jack Armstrong background and his Senate record of devotion to high-minded and moderately liberal causes, Bradley could single-handedly shift their party to the political mainstream, the required route for regaining the Oval Office.

When Bradley announced his Senate reelection bid last month, he asserted that he expected to serve out his full six-year Senate term. But party pros pointed out that Bradley had prefaced this seeming disclaimer of presidential interest with the qualifying phrase: “If you asked me today. . . . “

“I can’t speak for him,” said Michael Kaye, a media consultant and longtime Bradley adviser. “But I think he feels that when he’s ready, he’ll run for President.”

Meanwhile, Bradley himself was willing to spell out for a reporter what it would take for him to consider himself ready for the presidency.

Of the presidential standards Bradley has established for himself, the one that he mentions first is a firsthand knowledge of how Americans of all sorts live and work. This is an understanding which Bradley has been pursuing with low-profile visits to such widely assorted locales as a Chicago tenement, an Indian reservation and the drug-ridden streets of a Newark police beat.

“I’m somebody who has to physically experience an environment in order to know it as well as I would like to know it,” Bradley explains. “I recognize this is impressionistic, not scientific,” he concedes. “People say, ‘You sound like Walt Whitman.’ Well, I’ll take that comparison.”

More conventionally, Bradley has been working to improve his much-maligned speaking style. In his Earth Day talk to a throng of 10,000 at Liberty State Park here in Jersey City, Bradley showed definite signs of improvement, driving home the perils of pollution, by dramatizing the plight of fish doomed to swim in polluted waters.

“Ask yourself do you want your children to swim with those fish? Do you want the children to eat those fish?” Bradley demanded.

“No!”the crowd shouted back.

As he ambled through the park, shaking hands and signing autographs, the 6-foot, 5-inch Bradley seemed eminently accessible and relaxed.

“Hey, Bill,” shouted one longtime Knicks fan. “How about one more jump shot for us?”

“Sorry,” Bradley replied. “The heart is willing but the knees are weak.”

Some who have worked with Bradley describe him as an enigmatic figure with a strong sense of privacy. Thus, some politicians suspect that even if Bradley reaches the state of political readiness to which he aspires, he might avoid taking the presidential plunge for personal reasons. “To run for President means you have to sacrifice everything else for that goal, including your privacy,” said former New Jersey Gov. Thomas H. Kean, a Republican who came to know Democrat Bradley through their collaboration on the state’s problems. “I’m not sure that Bradley is ready for that.”