The White House has launched a concerted effort to turn political weakness into strength on two critical election-year issues that have become big vulnerabilities for President Obama: rising gas prices and the controversial health-care law.

At the heart of Obama’s strategy are attempts to dispel Republican claims that his policies have helped drive up the cost of gas, and to improve public opinion of the health-care law, which has been a source of GOP derision for two years.

After months on the defensive, the president is trying to remake both topics into the selling points they were in 2008.

On Wednesday, he began a two-day energy tour that will take him to Nevada, New Mexico, Oklahoma and Ohio to champion investments in new energy sources and deflect Republican accusations that he is responsible for the jump in gas prices.

On health care, Obama and his allies have begun promoting the law anew in op-ed pieces and local appearances as the measure heads for a three-day hearing in the Supreme Court next week.

Health and Human Services Secretary Kathleen Sebelius, Agriculture Secretary Tom Vilsack and Labor Secretary Hilda L. Solis have been dispatched to Missouri and Florida and to meetings with college newspapers, farming publications and Spanish-language media outlets. Several publications favorable to the administration are running op-eds by Surgeon General Regina M. Benjamin and White House adviser Valerie Jarrett touting the overhaul.

Watching as these issues continue to drag down the president’s approval numbers, advisers this week held briefings at the White House and at campaign headquarters in Chicago to promote their “all of the above” energy plan.

They are also targeting women and other groups with appeals showcasing the provisions of the Affordable Care Act that polls find Americans most favor, including coverage for adult children and preexisting conditions.

None of this activity changes the reality that the health-care bill is a political vulnerability for Obama. In the latest Washington Post-ABC News poll, a majority of Americans said they want the Supreme Court to repeal at least some portions of the law.

But the president’s focus was on energy Wednesday as he visited the Copper Mountain Solar 1 plant in the Nevada desert to highlight the future of solar energy — and to ridicule Republicans for trying to trim federal funding to develop it.

“If some politicians get their way, there won’t be any more public investments in solar energy,” Obama said. “These folks dismiss the promise of solar power and wind power and fuel-efficient cars. . . . If these people were around when Columbus set sail, they would’ve been founding members of the Flat Earth Society.”

From a symbol of new energy, Obama traveled to a symbol of the old — oil and gas production fields on federal land outside Carlsbad, N.M., in another important state in the presidential election. More than 70 rigs are in production there across a plain of red earth.

White House officials have emphasized that, despite GOP contentions that Obama has turned his back on the domestic oil and gas industry, oil production is up 13 percent on federal lands over his term.

Obama spoke at twilight, flanked by a pair of oil rigs, an American flag whipped by the wind behind him. “You wouldn’t know it from listening to some of these folks running for office — I won’t mention their names, you know who they are — but producing more oil here in our own country has been, and will continue to be, a key part of our energy strategy,” the president said.

“But here’s the thing,” he said. “Drilling for oil can’t be the only part of our energy strategy.”

Much of the Republican criticism of Obama on energy has centered on his rejection of a Canadian firm’s application to build and operate the 1,700-mile Keystone XL pipeline, which would have straddled the United States to link oil sands in Canada to refineries on the Gulf Coast.

Obama said his decision was in response to a “rushed and arbitrary deadline” that congressional Republicans set as part of legislation extending tax cuts.

Many environmentalists celebrated the decision. The administration has said the company, TransCanada, can resubmit the application with a new route that avoids the environmentally sensitive Nebraska Sand Hills.

On Thursday, Obama plans to visit Cushing, Okla., which would sit at the start of the southern leg of the proposed pipeline. White House officials say he will issue a memo calling for an expedited review of that stage of the project.

A Washington Post-ABC News poll published this month found that 65 percent of those surveyed disapproved of Obama’s handling of gas prices. Half of those surveyed believe that he can do more to bring them down.

Yet compared with those who answered the same question about George W. Bush in 2006, fewer believe that Obama can do something to lower oil prices, suggesting that he is facing less blame for gas prices than his predecessor did.

That could change if the Republicans continue to hammer him on the issue. Crossroads GPS, a GOP group, has begun airing a new advertisement on the subject.

And presidential candidate Mitt Romney made a point of focusing on Obama’s energy trip at an appearance in Maryland.

“The man can speak well,” Romney said of Obama, but “how he can explain that some of these policies make a lot of sense, I don’t know. . . . When he gives $500 million to [bankrupt solar company] Solyndra — which, by the way, had a number of campaign contributors there — he picks winners and losers. Well, actually in this case, just losers.”

Staff writers Ed O’Keefe and Aaron C. Davis and polling analyst Scott Clement contributed to this report.