IF POLITICS were the Olympics, next Thursday's bipartisan health care summit would be the can't-miss prime-time event. Although it's being billed as a search for bipartisan compromise on health care, what this high-profile parley will really be is a battle for the hearts and minds of the public. If the two parties shared the same goal and merely differed on the means of accomplishing it, real compromise might be possible. But in this case, they have very different objectives. Democrats want to address the problem of the uninsured with a big bill that would move the country to near universal care, while offering safeguards against insurance company abuses, plus wide-ranging experiments in curbing costs. Republicans don't believe the country can afford a dramatic expansion of health coverage. They prefer to focus on more limited ideas to help small businesses, restrict malpractice awards, and make it easier for people to save for medical expenses. Unless and until one side abandons its philosophical approach, it's hard to see any substantive agreement emerging from the Feb. 25 meeting {ndash} assuming it actually takes place. Although they now lack the 60 votes required to overcome a Senate filibuster, Democrats still hope to enact a comprehensive bill. Their favored route remains having the House pass the Senate bill, with a side agreement about fixing it through the reconciliation process, which can't be filibustered. But moving forward in that, or any other, fashion on a comprehensive bill will prove difficult if the public remains opposed to the Senate legislation. And the odoriferous back-room deals necessary to win the support of some conservative Democrats, plus the propaganda assault on the bill, have clearly taken their toll. For months, polls have shown more Americans are opposed to it than support it. On the other hand, some of its key components remain popular. The challenge for President Obama, then, is to use this summit to rally public opinion back behind him on health care reform. For the summit to be a success, the president needs to accomplish at least three things. First, he needs to explain to people who already have health care why this legislation will be good for them. Concern about one's fellow citizens is a laudable impulse, but a voter's first question is usually this: What's in it for me? And that's one place where Democrats have failed in their public presentation. Second, he needs to elucidate why a comprehensive approach works better in an area as complex and interwoven as health care. That is, why it's hard to address costs effectively without also addressing coverage - and vice versa. In so doing, Obama needs to shift away from his party's reflexive critique of the opposition. Democrats have spent months disparaging congressional Republicans as a group with no ideas beyond saying no. The more accurate criticism - and the more promising argument - is that the GOP's favored nostrums aren't equal to the size of the problem. And if Obama can't persuade skeptical voters why comprehensive legislation is needed and why Republican ideas don't measure up? Well, then, he'll have lost both the philosophical and the public-relations battle. Finally, the president needs to put a spotlight on the GOP tactic of using the filibuster rule to require that any legislation of any consequence must have 60 votes to move forward. That's become such a routine thing that people tend to accept it as the way Senate business must be done. However, for much of the Senate's history filibusters (or threats of same) weren't an everyday occurrence. There's a tendency to regard the legislative process as incomprehensible inside baseball, and so not to explain it to the public. That's a mistake. Voters need to understand that abuse of the filibuster has made it exceedingly difficult to address big issues in Washington. Yet that argument will only prove effective if the president succeeds in swinging public opinion back behind the Democratic approach to health care. Next week's summit may be his last best chance to retake that crucial high ground. Scot Lehigh can be reached at lehigh@globe.com. 