TO UNDERSTAND WHY President Bush is relatively unpopular, one only has to look to the case of Gov. Arnold Schwarzenegger of California. After his election in November 2003, Schwarzenegger experienced a political honeymoon. He governed mostly by compromise and without pushing for sweeping change. And his popularity, measured by how people feel about his performance as governor, soared. That lasted for more than a year. Now Schwarzenegger has gotten serious. He's called for a special election to limit government spending permanently, curb teacher tenure, and take redistricting out of the hands of the legislature, which is controlled by Democrats. His popularity has plummeted.

Bush's popularity dropped in 2003 after the terrorist insurgency spread in Iraq. And except for a blip or two, it hasn't risen significantly since, even after his effective campaigning last fall, his reelection, and his dazzling inaugural address. Instead, his job performance rating in the Gallup Poll has dipped further--from 52 percent in January to 47 percent now.

Bush doesn't have the second-term blues, his administration hasn't lost its zeal, and he hasn't been troubled by scandal or the lack of a clear policy agenda. Nor is he suffering solely from his single-minded pursuit of Social Security reform. Like Schwarzenegger, the president has taken on a string of big issues--Iraq, a drastic foreign-policy overhaul, judges, plus Social Security--with predictable results. These are issues that generate political conflict. They upset settled practice, rile various institutions, stir strong opposition, and keep poll ratings low. For an activist president, lack of popularity is part of the package.

It's sad but true that our political system, assuming the economy is not in the tank, rewards presidents (and sometimes governors) for doing little. President Clinton benefited from this. His second term was largely unproductive. He balked at Social Security or Medicare reform. The war he fought in the Balkans consisted of bombs dropped from such high altitudes that American warplanes faced minimal risk. He refused to consider sending ground troops. The result: no American casualties. He did nothing to ease the stock-market bubble or deal with the looming recession. He got along with France.

Clinton's poll numbers remained at lofty levels and still do today. His job-performance rating averaged above 60 percent in his second term. During the week in which the House of Representatives voted to impeach him, his rating was 73 percent, the highest of his presidency. In hindsight, more than 60 percent of adult Americans still regard his presidency as a success. Asked recently if they favored a third term for Clinton, 43 percent of voters said yes. Only 27 percent said they wished Bush would serve another term.

President Reagan, while hardly as unproductive as Clinton in his second term, also profited a bit from the do-little syndrome. His approval rating in June 1985 was 58 percent, well above Bush's today. True, he achieved tax reform, but that was at a time when leading Democrats were on board. And he got along famously with Soviet leader Mikhail Gorbachev, all the while marching toward victory in the Cold War. But Reagan had quickly abandoned Social Security reform when the Senate frowned on it and declined to fight for serious spending cuts. Had he pursued those issues in his second term, his popularity would no doubt have sagged.