Full tank of premium

John Kerry may have stopped for gas on March 30, but he never detoured from his campaign message for the day. When the Massachusetts Democrat, en route to a San Diego stump speech, stopped to fill up his nine-car caravan at a Shell station, TV cameras were there to capture the stalled traffic on the busy street -- and the spinning dials on the pump.

The price per gallon at Sen. Kerry's station of choice: $2.15 for regular and $2.37 for premium. Those are the kinds of prices that make consumers wince and Democrats smile.

"If the gas prices keep rising at the rate they're going now, Dick Cheney and George Bush are going to have to car-pool to work," Sen. Kerry later told a crowd of students at the University of California-San Diego. "Those aren't Exxon prices. Those are Halliburton prices," he said, getting in an extra dig at the vice president's former company.

With gas prices rising rapidly nationwide -- $1.80 a gallon in most places, $2-plus a gallon in California -- Democratic strategists believe they've found an issue that could fuel voters' discontent. Prices have risen 11.5 percent since Mr. Bush took office, and they're likely to go even higher. Just one day after the Kerry campaign stop in San Diego, OPEC oil ministers meeting in Vienna voted to cut production by 4 percent.

Sen. Kerry says he would bring prices back under control by pressuring OPEC to increase production, encouraging the use of alternative energy, and temporarily suspending contributions to the nation's Strategic Petroleum Reserve.

That final proposal drew a sharp response from Republicans, who charged that Sen. Kerry was playing politics with national security. "It's important that we have the necessary resources in the event of a severe disruption of supply," said White House spokesman Scott McClellan. Rather than curtailing contributions, Mr. Bush plans to boost the reserve to 700 million barrels, enough to keep the country running temporarily in case a catastrophic event such as war or natural disaster were to cut off the supply of outside oil.

Energy Secretary Spencer Abraham called the 700-million-barrel target a "critical national-security objective" and scoffed at the idea that curtailing deposits to the reserve would have any appreciable impact on prices at the pump. An extra 150,000 barrels a day eventually flowing to local gas stations would be "fairly negligible" considering the worldwide output of 86 million barrels daily, he told a Senate committee.

With a new poll showing that more than two-thirds of Americans now view high fuel costs as a "crisis" or a "major problem," however, the Bush team could hardly afford to play defense on the issue. Even as Sen. Kerry headed to California for his energy speech, Republicans hit the airwaves with a tough new TV ad charging that the Massachusetts senator once supported a 50-cent-per-gallon gas tax that would have cost the average family more than $600 a year. The ad is running in 18 battleground states at a cost of $6.5 million.

Mr. Bush also made sure his opponent wouldn't be the only one with a soundbite about high gas prices on the evening news. Hours after Sen. Kerry made his speech at UCSD, the president told a campaign rally in Wisconsin that "gas taxes would hurt the economy. There are some in the other party in Washington who would like to raise gas taxes. I think it would be wrong."

With OPEC's production caps likely to keep prices high through the spring and into the busy summer driving season, the issue isn't likely to go away any time soon. And history proves it's an issue the White House can't ignore. Some experts predict gas prices could hit $3 a gallon, shattering the inflation-adjusted record of $2.80 a gallon. That level was last hit in 1980, when Jimmy Carter was president -- and just before he lost his bid for reelection.