President Bush has formidable obstacles to reelection, but he served a reminder last week that he is a politician with formidable strengths.

Anyone who doubts it should spend some time watching the shirtsleeves campaign. In five days of energetic campaigning through five swing states, Bush looked and sounded like someone dropping by a neighbor's lawn party -- no coat, no tie, rolled-up sleeves, and conversational speeches in which he implored voters to "put a man in there who can get the job done."

In loosening his style, Bush tightened his message. Fielding friendly questions at "Ask President Bush" forums, or lathering up the crowds at pep rallies like the one here on Saturday afternoon, he presented his case for reelection with a force and fluency that sometimes eluded him at important moments over the past year.

The message Bush offered at these events has been familiar for months: that he is a plain-spoken conservative who knows his mind and is resolute in crisis, and that his Democratic opponent, Sen. John F. Kerry, is the opposite on each count. But crafting an argument and finding the words and cadences to deliver it effectively can be different things.

Two weeks before the Republican National Convention, Bush's performances in recent days suggested someone who has settled on a comfortable marriage of message and style. Applause lines, anecdotes, and wisecracks at Kerry's expense rolled off at a steady clip. There was a buoyant, jaunty manner that announced a politician who is relishing his fight.

Bush has a complicated political task in the remaining 78 days of the campaign. It is to take the offensive on two dominant issues -- the Iraq war and the economy -- where facts have placed on him on the defensive.

The failure to find the weapons of mass destruction in Iraq was one place where Bush on the stump flips the discussion from his vulnerability, a war rationale that has not been borne out by evidence, to Kerry's -- a trail of votes and statements that in Bush's telling reveal the challenger's indecisiveness.

"See, I thought we were going to find stockpiles," Bush acknowledged at a voter forum in Beaverton, Ore. "So did everybody else, you know. . . . We haven't found them yet, I recognize that."

But he insisted that Congress acted on the same intelligence he did in giving bipartisan approval to an Iraq war resolution, and that "the world is better off because Saddam Hussein sits in a prison cell."

But this background serves mostly as preface to an attack on Kerry. At each stop last week, Bush regaled his audiences by noting that the Democrat voted for the Iraq war resolution and then "declared himself the antiwar candidate" in last winter's primaries, and now, having "found a new nuance," has said he still "agrees it was the right decision to go into Iraq."

"And I want to thank Senator Kerry for clearing that up," Bush chortled. "Although I caution you, there are still 80 days left where he could change his mind again."

He continues by noting that everyone in Congress voted for his $87 billion appropriations request on Iraq except for a "small what I would call out-of-the-mainstream minority of 12" Democrats, "and two of those 12 are my opponent and his running mate."

"You might remember his initial explanation," Bush told partisans at the Iowa event. "He said, 'I actually did vote for the $87 billion before I voted against it.' That doesn't sound like the way people in Sioux land talk. The pressure got on a little bit about that vote. Then he said, well, he's proud of the vote. And he went on to say, the whole thing is a complicated matter."

Then came what is becoming one of the standard applause lines in Bush's stump speech: "There's nothing complicated about supporting our troops in combat."

On the economy, Bush's approach is to acknowledge that his term has been marked by "hard times" but that "we've overcome it because of well-timed tax cuts."

If last week's lines are a reminder that Bush can be a skilled political performer, the year has also produced reminders that he can be the opposite. The State of the Union address in January did little to expand Bush's support or frame his reelection themes, polls afterward showed. Some high-profile news conferences and interviews showed Bush stumbling to get off the defensive.

Such middling efforts and missed opportunities have helped place Bush in his current predicament, running essentially even with Kerry and well behind the public approval ratings scored by other recent presidents who succeeded in reelection efforts. For all these troubles, however, the week showed that Bush has not let a hangdog air settle over his campaign, as it did over such losing efforts as his father's 1992 reelection effort or Republican Robert J. Dole's challenge to President Bill Clinton in 1996.

To the contrary, Bush was drawing appreciative crowds -- many of whom, judging by the signs they carried and questions they asked, were the Christian conservatives whom the president and his political aides have steadfastly courted. For the most part, Bush on the stump touches on the cultural issues important to these voters using indirect language rather than addressing specific policy controversies, such as his opposition to abortion, and support for a constitutional amendment banning same-sex marriage and for federal restrictions on stem cell research.

Here in Sioux City, for instance, Bush said "we stand for institutions like marriage and family," and also for "a culture of life, in which every person matters and every person counts."

"We stand for judges who faithfully interpret the law, instead of legislating from the bench," he said.

While Bush's style sounds conversational, his speeches, made with only occasional glances at notes, are increasingly practiced, with the same stories and arguments appearing in the same places.

Still, there are occasional variations. In one telling of his riff about the majesty of the Oval Office, he notes that it leaves any visitor speechless -- except for "my mother, who walked in and continued to tell me what to do."

That line was in Las Vegas. In Florida, however, he made the same point but said that the Oval Office is so powerful "it's the kind of place where my mother walks in and feels so overwhelmed, she won't tell me what to do."

A casually dressed President Bush holds a baby at the end of a campaign rally in Sioux City, Iowa.