In the past week, John McCain and Bill Bradley have been pushed into revealing parts of their medical history in order to deal with adverse developments in their campaigns for the Republican and Democratic presidential nominations. The two friends, who will join hands in New Hampshire tomorrow to promote campaign finance reform, also have a lesson to teach on the tricky question of privacy in presidential politics.

In the public forums and roundtables I've attended this year, nothing seems to bother people more about today's journalism than the blurring of lines between the public records of candidates and their private lives.

Such a concern is to be expected after the horrendous experience families had in being subjected to the grossest details of President Clinton's liaisons with Monica Lewinsky. Voters clearly are determined to buy themselves an insurance policy against that kind of embarrassment when they choose a new tenant for the Oval Office next year.

But the aftereffects of the Clinton scandal are much broader. Time and again, on college campuses and at town halls, reporters are being asked to justify what the questioners call "invasions of privacy" and to weigh the impact of such "trespasses" on the willingness of able men and women to offer themselves as candidates.

The implicit--and occasionally explicit--question is: "Why would anyone run for high office, knowing that you people (the press) will rummage through everything in their backgrounds and expose every human weakness you can find?"

It is certainly the case that reporters at times have pushed their examinations of candidates' personal histories beyond decent limits. I wrote months ago, when Texas Gov. George W. Bush was being subjected to a blitz of questions about his possible use of cocaine in earlier years, that absent any evidence of drug abuse, such rumor-based interrogation was "harassment."

I still believe that. And I also believe that other generic "have you ever?"-type questions should be out of bounds. They are lazy shortcuts, not the serious reporting that needs to be done on presidential candidates' formative experiences and professional careers. Too often, they have no purpose other than providing a quick tabloid headline or satisfying someone's prurient curiosity.

But the McCain and Bradley developments serve as a reminder that there are personal matters--the kinds of things most of us properly choose to keep to ourselves--that do become matters of press and public interest when someone is running for president.

The health of a president--or a presidential candidate--is certainly one of them. We elect 435 members of the House and 100 senators. There are nine members of the Supreme Court. But we have only one president. Before the nominating conventions, we have no idea who the vice-presidential candidates will be. Even after the election, we rarely can judge that stand-in's capacity to fill the top job.

So the public has every right to know what, if any, health problems may affect a would-be president's capacity to do the job.

McCain and Bradley both acknowledged that fact--but only after it became necessary. The Arizona senator released about 1,500 pages of medical records, dating back to his release from a Vietnam POW camp, in order to stop rumors that his lengthy imprisonment had left him emotionally unstable.

Bradley issued his health data after an irregular heartbeat forced him to cancel some campaign events on the West Coast last week. The former New Jersey senator disclosed for the first time that he had been diagnosed with this quite common form of "atrial fibrillation" back in 1996 and had been taking daily medication for it since 1998.

Both of them would have been well advised to have made the disclosures sooner than they did. McCain should have been aware that once he became a presidential candidate, the flashes of temper for which he is known among colleagues in the Senate and political associates back home would certainly be discussed.

Bradley had had more than a half-dozen incidents of his heartbeat going awry for brief periods of time, including one earlier in the presidential race. He said he had planned to make his medical history public this week, but when the problem popped up last Thursday, his hand was forced.

On the available evidence, neither McCain nor Bradley has a medical problem that should cause any concern. But the lesson of their experiences for other candidates is clear: Disclose your medical records early. And then fight like hell to keep private those other aspects of your life that are nobody else's business.