By year's end, the tables had turned. With U.S. casualties in Iraq mounting and no end in sight to postwar occupation, Mr. Bush may be counting on a surging economy to prop up sagging public support for his handling of foreign policy.
"For President Bush, it's been the worst of years and the best of years," said Allan Lichtman, a political science professor at American University. "He's seen his major foreign policy initiative go awry but just in time, the economy is recovering."
If the economy continues to rebound and Mr. Bush can capitalize on the December capture of former Iraqi leader Saddam Hussein, Democrats may be hard-pressed to deny Mr. Bush a second term, analysts say.
Early in 2003, Mr. Bush was laying the groundwork for war and finding reluctant support among Democrats. Even presidential hopeful Sen. John Kerry, D-Mass., acknowledged that the case against Saddam was "real and compelling."
Most of the other Democrats in Congress seeking the party's nomination - including Rep. Dick Gephardt of Missouri and Sens. Joe Lieberman of Connecticut and John Edwards of North Carolina - also voiced support for war.
Former Vermont Gov. Howard Dean was a notable exception. The then-little-known presidential candidate openly criticized the war even during the peak of Mr. Bush's popularity in May, when Mr. Bush declared major combat over in Iraq after a triumphant landing on the deck of a returning aircraft carrier.
Once considered a long-shot candidate, Dean would catapult from obscurity to Democratic front-runner during the summer. Separately, coalition forces failed to find Iraqi weapons of mass destruction and critics questioned the handling of prewar intelligence and the pace of rebuilding.
By midsummer, the White House was in full damage control mode over Iraq. President Bush took responsibility for repeating in his State of the Union address a discredited claim that Iraq was trying to buy raw uranium in Africa. The search for banned weapons - once a key basis for military action - now was "not of immediate consequence," said Deputy Defense Secretary Paul Wolfowitz.
Meanwhile, Democrats continued to bash Mr. Bush on the economy, calling the 3 million jobs lost since he took office the worst record since Herbert Hoover in the Great Depression. The stock market went into a three-year tailspin and Gephardt labeled Mr. Bush a "miserable failure" on Iraq and the economy.
But as the holiday season approached, new economic data presented good news for the Republican incumbent: rapid growth that surprised most economists, indications the job market could be turning around and the Dow Jones industrial average crossing 10,000 for the first time in 18 months.
At the same time, the arrest of Saddam has silenced some of Mr. Bush's foreign policy critics - at least temporarily - although guerrilla attacks on U.S. forces have continued.
"It's a huge Boost for Mr. Bush coming at a time when he'd already gotten some other positive economic news," said Norman J. Ornstein, an expert on the presidency at the American Enterprise Institute.
But Ornstein warned against making dramatic judgments based on a single event.
"If it doesn't result over the course of the next eight or nine months in a significant lessening of the turmoil in the country and the attrition rates, then it's not going to be seen at that point as any great triumph," he said.
In fact, Saddam's appearance as "kind of a pathetic fugitive on the run" rather than a great orchestrator of insurrection might mean insurgents would continue to attack American troops regardless of his capture, Ornstein said.
Timing is everything as the clock ticks down to Election Day on Nov. 6.
"If things improve in Iraq and the economy gets better, there aren't too many easy targets of opportunity for the Democrats," said Burdett Loomis, a political science professor at the University of Kansas.
President Bush seems to have learned from the mistakes his father, the first President Bush, made in 1991 when he won the Persian Gulf War but lost re-election. Some criticism of the first Bush suggested that he was out of touch on domestic matters.
The son has followed through on a number of campaign promises on economic issues. He pushed three successive tax cuts through Congress and increased domestic spending despite a surging federal deficit approaching $500 billion. The sweeping Medicare legislation Mr. Bush signed in December will cost about $400 billion over 10 years.
Loomis said Mr. Bush's tactics are clear: Rev up the economy as much as possible in the election year without too much concern about the future.
"Bush and his advisers are proving themselves masters of political timing because they have pushed back everything," Loomis said. "The benefits come up front while the costs, which may be truly substantial, are deferred."
The question for Democrats is how to frame those long-term problems, either in Iraq or on the economy, in a way that is meaningful to voters.
"Everyone is talking about the deficits, but George Bush loves those deficits," Lichtman said. "The deficit issue rings like a bell without a clapper. As long as people feel good, the deficit is just an abstract number."
President Bush's Democratic rivals have pledged to repeal all or some of the tax cuts and labeled the Medicare measure a gift to drug companies that does too little for seniors. Dean called the Medicare plan "a $400 billion charge to our grandmother's credit card so that President Bush can be re-elected."
"What's going to matter is how people feel about their country eight to 10 months from now," Lichtman said. "If they feel pretty good about the economy and foreign policy is not an absolute unmitigated disaster, like Vietnam in 1968, then Mr. Bush is going to be tough to beat."