President Obama won a major legal victory on Thursday. The question now is whether Mitt Romney and the Republicans can translate the divided Supreme Court’s decision on the health-care law into a political victory in November.

Republicans were clearly anticipating a different outcome. All their rhetoric, all their body language and many of their preparations were based on the assumption that the justices would deal a significant setback to the president, at a minimum by striking down the individual mandate. After all, it was Republican leaders — strategists — who were warning their colleagues this week not to gloat once the ruling was announced.

Instead, it was the White House and the Democrats who carried the day. The decision will help Obama secure a political legacy for having enacted — against huge and united Republican opposition — the most far-reaching piece of social legislation since Medicare and Medicaid almost half a century ago.

The decision also will give the president a fresh opportunity to try to win the political argument over the law, or at least do a better job of trying to sway a skeptical electorate than he and his team have done since the measure was enacted. “Today’s decision,” he said, “was a victory for people all over this country whose lives will be more secure because of this law and the Supreme Court’s decision to uphold it.”

There was clear surprise about the court’s decision, especially the route that Chief Justice John G. Roberts Jr. and the four liberal justices who joined him took to uphold the controversial requirement that all Americans purchase health-care coverage or pay a penalty. But their ruling left the political divisions as sharply etched as ever. What the justices did was to send the issue back into the political arena for ultimate resolution.

William Galston, a Brookings Institution scholar, noted in the run-up to the decision announcement that “winners celebrate and losers mobilize.” Mobilizing is what Republicans intend to do. They asserted that their setback will provide the motivation in the GOP base to produce a big victory in November.

Republicans returned with even greater emphasis to the rallying cry that has sustained them since Obama signed the measure into law more than two years ago: “Repeal and replace.” With the most controversial element of the law declared constitutional, the avenue left for Republicans to change it is the ballot box in November.

Romney sounded that theme when he spoke not long after the court ruled, saying he would do on Day One what the court did not do. “If we want to get rid of Obamacare,” he said, “we have to get rid of President Obama.”

Republicans think they have several potentially potent arguments to carry into the election. The first is that the health-care law and the mandate constitute a huge tax increase on the American people. The second, long used by conservatives, is that the law remains an unacceptable expansion of power for the federal government and a huge overreach by the president.

Before the decision announcement, longtime Republican strategists were arguing that, even with a victory in the high court, the president would be saddled with defending a law that remains generally unpopular with the public and deeply disliked by the Republican base — “the single most unpopular thing Obama has done,” as one strategist put it.

After the ruling, strategist Terry Holt summed up the Republican argument this way: “What an accomplishment for Obama,” he said in an e-mail. “He is author of the most massive new tax in American history. And for what? To finance an unpopular law that threatens the quality of heath care for millions of American seniors. This will galvanize the right and leave the center of the Democratic Party to the mercy of an angry electorate.”

But pressing for total repeal may not be as simple as some Republicans believe. For one thing, even if they controlled the White House, the House and the Senate next year, Republicans would struggle to get 60 votes in the Senate to overturn the legislation. Are they prepared to spend months fighting over health care and leave themselves open to the charge that they weren’t paying attention to the economy — the same thing they said of Obama?

Ed Goeas, a GOP pollster, said before the ruling that it was important, in pressing for repeal, for Republicans to be cognizant of the fact that many of the law’s provisions are popular. “People strongly dislike Obamacare, but they’ve kind of forgotten why they don’t like it,” he said. “But they do remember what they do like.”

Democrats certainly saw the post-court politics differently. Now that the constitutional question has been resolved, they said, the president can focus on the provisions that people favor. “This fits the mood of the public,” Democratic pollster Celinda Lake said. “They want to keep what works and move on to fix what doesn’t.”

Whether that will work with independent voters, who have been more negative than positive in their assessments of the law, is the real question. Ross Baker, a political scientist at Rutgers University, said Obama still may have trouble changing public opinion about the health-care law, even with the Supreme Court on his side. “The constitutionality of the Affordable Care Act pales, politically, beside the need . . . to make your case for reelection tethered to a program that remains widely unpopular,” he said.

For the time being, the court ruling put health-care reform back in the center of the political debate. Romney will no doubt make “repeal and replace” a continuing part of his message. But Romney’s team long has assumed that jobs and the economy will determine the outcome in November, and other Republicans said he should never lose his focus on that issue.

Ken Khachigian, a California-based Republican strategist, said the issue will have “zero influence” on the outcome of the election. “Romney would make a huge mistake if he allowed himself to be diverted from the core economic issues,” he said.

For Obama, the elation that he and his advisers may have felt Thursday could quickly dissipate if more bad economic news occurs. It is a long time until November, and the economy, domestically and internationally, remains extremely fragile.

“This is going to be the biggest week of the campaign,” Republican strategist Vin Weber said, referring to the court decision, “until we get to the June jobs report next week. The economy issue writ larger is going to be the dominant issue of the campaign.”

More than anything, the decision heightened and helped to clarify the choice for voters in November. Obama and Romney are offering a choice between the starkly different philosophies and sharply contrasting policy paths.

With the health-care law having survived largely intact in the courts, voters become the ultimate arbiters of which path and leader they prefer. The justices may have narrowly resolved the legal issues, but not the political divisions. As political scientist Merle Black of Emory University put it, “American politics just became even more divisive and polarized.”

For previous columns by Dan Balz, go to