US President George W Bush has launched his bid for re-election, filing papers declaring his intention to contest next year's vote.
Bush is hoping for a clearer victory than in 2000
White House officials presented the papers to the Federal Election Commission, administration officials said.
The move permits Mr Bush to raise funds, hire staff and open a campaign office.
Despite a slow economy, the president's popularity has soared since the 11 September 2001, attacks on America and his decision to go to war against Saddam Hussein.
In the 2000 election, Mr Bush defeated Democrat challenger Al Gore following a Supreme Court ruling and a cliff-hanger count.
The next elections are due to be held in November 2004.
War on terror
The BBC's Nick Bryant in Washington says George W Bush is determined to avoid the political mistakes of his father, who won a Gulf war in 1991, only to lose the presidential election the following year.
Then as now the economy was spluttering and Bush Senior was deemed to have spent far too much time on foreign affairs, rather than the domestic concerns of American voters, our correspondent says.
Mr Bush's campaign is likely to focus on Republican plans to stimulate the economy with a multi-billion dollar tax-cut plan.
His handling of the fight against global terrorism and the issue of national security is also expected to play a prominent role.
In contrast, Democrats are expected to highlight the sluggish pace of economic growth and instability in Iraq following the downfall of Saddam Hussein's regime.
Currently Mr Bush is in a strong position - recent opinion polls put his approval rating at more than 70%.
The battle plan to keep Mr Bush in the White House will be led by the president's political adviser, Karl Rove.
He will be helped by a campaign manager, yet to be named but said to be Ken Mehlman, the White House's political director.
The first appeals for campaign money will be made in the next few days, and Mr Bush himself will make his first appearance at a fund-raiser in June.
In the 2000 campaign, Republicans raised more than $100m, breaking previous records.
Analysts say Mr Bush could double that total after parts of a campaign finance reform law, which aims to limit the influence of money on US politics, were ruled unconstitutional by the courts.