With the filing the other day of a simple federal form — now there’s an oxymoron for the ages — the 2004 presidential campaign has begun in earnest.

The form permits George W. Bush and his allies to raise money for his re-election battle, and it acknowledges what was well understood and was well under way for months. It isn’t so much that the campaign for president is permanent. It’s also that the presidency is a permanent campaign.

This aspect of the American political system cannot be laid at the (clay) feet of Karl Rove, whom the Democrats blame for everything, perhaps even the late-inning pitching woes of the Pittsburgh Pirates. The pre-eminent practitioner of the permanent presidential campaign was the chief executive between the two Bushes, Bill Clinton, who devoured poll results with the avidity he also applied to Big Macs and mango ice cream.

The president enters the formal part of his presidential campaign with rare mastery of the sound bite (“dead or alive”) and the visual image (the “Top Gun” landing on the deck of the aircraft carrier USS Abraham Lincoln).

He has also married foreign-policy achievement (the wars in Afghanistan and Iraq) with domestic-policy emphasis (the day those forms were filed, he was quoted just about everywhere saying he was “focusing my attention … on helping people find work.”) The Bush family hasn’t forgotten the last time it ran a presidential re-election campaign.

And yet, in GOP circles, there remain worries that the son might not necessarily avoid the sins, and the heartbreak, of the father.

At this point in his term, the first President Bush was defending a tax increase he negotiated with the Democrats, causing a fissure within the Republican Party that hampered his political latitude right through the Houston convention. The current President Bush has no such problem — there will be no pitchfork rebellion in New Hampshire next January like the one mounted among Republicans in 1992 by Patrick J. Buchanan — but he hasn’t stilled doubts on the economy.

Surely the most troubling poll result of the president’s first term came with this month’s New York Times/CBS News poll, which showed that two out of three Americans approve of Bush’s conduct of the presidency — but that the slice of Americans who have confidence in his ability to manage the economy fell to 47 percent. Rule of thumb: Any poll finding involving any president that comes in under 50 percent is trouble.

Stephen Moore, the libertarian thinker, has another sober reminder for the president: Not once in the last century has a president who has presided over a falling stock market been re-elected. The jobless recovery of the George W. Bush years has a sibling, a postwar boost without a boom. The Washington Post/ABC News poll shows that, by a slim margin, 48 percentage points to 42, the public believes most Americans are not as well off or in about the same shape financially as they were when Bush first became president. In their hearts, as conservatives have liked to say since 1964, they know the poll finding is right.

At the same time, a new study by Ruy Teixeira in The Washington Monthly suggests that the demographic groups that favor the Republicans are shrinking, while the groups that favor the Democrats are growing.

And yet the Democrats who sparred without sparkle in this spring’s inaugural debate in South Carolina face an immensely difficult challenge in toppling the president. There are two reasons, and they both involve expectations — the soil into which national political prospects are planted.

The first is the public’s modest expectations for Bush after his election in 2000. The Texas governor lost the popular vote, faced questions about his legitimacy as the victor in a contested election, and then began his presidency by poor-mouthing the economy and perhaps accelerating a recession he was determined to blame on his predecessor. But for all the low expectations, Bush has displayed remarkable leadership skills — skills now admired even by his Democratic rivals and by Sen. John S. McCain of Arizona, who belittled Bush while the two were contending for the GOP nomination.

The second is the public’s expectations of the president on the economy. Look at the month after the first Gulf War: 70 percent of the public, according to the Washington Post/ABC News poll, said the war with Iraq led them to have more confidence in President George H.W. Bush’s ability to handle the country’s other problems. Now look at the month after the second Gulf War: Only 43 percent of Americans, according to the same poll, feel the war with Iraq makes them have more confidence in President George W. Bush’s ability to handle the nation’s other problems.

In those 27 percentage points is a margin of error that may prove decisive for the president.

Ordinarily the phrase “margin of error” reflects the wiggle room pollsters provide themselves when they calculate public attitudes. In this case we can employ the phrase to refer to the tolerance the public may extend to the president for the persistent economic woes that are now the most arresting topographical feature on the American political landscape. A forgiving public may extend that margin of error to Bush for economic woes that six out of 10 of Americans don’t believe the administration should be blamed for.

Bush has not presided over lucky times; any era blotched by terrorist attacks and bloodied by two wars can only be regarded as tragic. But the president nonetheless is a lucky man. The question the American people will confront in 18 months is whether he has made his own luck. If they conclude that he has, he’ll be re-elected, even if the economy hasn’t rebounded.