TAIPEI, Taiwan (AP) _ The latest guy giving President Bush headaches isn't an AK-47 toting leader of a shadowy terrorist group. And he's not a Stalinist recluse with nuclear ambitions. He's Taiwanese President Chen Shui-bian _ a 52-year-old workaholic attorney who wears plain blue suits and big wire-framed glasses, and who runs one of Asia's most vibrant democracies and richest economies.

Chen landed in Bush's inbox of problems by calling for Taiwan's first island-wide referendum. He says the March 20 vote will be on whether China should withdraw hundreds of missiles pointing at this tiny island.

The Taiwanese leader is under tremendous pressure to cancel the referendum, which Washington fears could lead to an independence vote that could spark a war with China. The two split amid civil war in 1949, and Beijing is demanding that the island agree to unify.

Once an enthusiastic supporter of Chen, Bush leaned on the Taiwanese leader this week, warning that America opposes unilateral moves to change the status quo. It was Chen's biggest slap from Washington since he took office four years go.

Some members of Chen's Democratic Progressive Party said it's too early to say if Chen would scuttle the referendum to preserve friendly relations with America, Taiwan's most likely defender if China ever attacks. Much depends on whether Washington keeps the heat on Chen.

Luo Wen-jia, a lawmaker close to Chen, doubted the president would back down on the referendum.

``He has already compromised by proposing this anti-missile vote'' and not calling an election that directly involves the touchy sovereignty issue, he said. ``The president may twist and turn, but he won't easily give up.''

In a 30-minute speech at his party's convention Saturday, Chen again seemed to reject Washington's concerns.

``No democratic country should describe Taiwan's efforts to realize democracy as provocation,'' he said, adding his thangthanking the international community _ ``including the United States'' _ for backing Taiwan over the past 40 years.

Chen is locked in what could be the biggest election battle of his life. He's being challenged by two parties that have combined forces to defeat him in the March election. Dropping the referendum would be extremely embarrassing, his supporters say.

Chen has a long history as a scrappy fighter. He grew up in poverty in southern Taiwan; his father was a factory worker and his mother was a day laborer. He has said the family milk supply came from U.S. aid packages.

Chen excelled at school and majored in law at Taiwan's top school, passing the bar exam before graduating and settling into a career as a maritime lawyer.

He showed no strong interest in politics until the late 1970s, when he began defending dissidents arrested during the martial law era. He later became a Taipei city councilman and a member of parliament, where he often stormed around the legislature tossing papers as his party pushed for greater democracy.

Chen's political career brought pain to his family. His wife, Wu Shu-chen, was paralyzed from the waist down when a truck ran over her three times in 1985. The couple believes it was a politically motivated murder attempt.

Chen's upset election victory four years ago snapped the Nationalist Party's five-decade grip on the presidency. The win was an amazing success story for the Democratic Progressive Party, which the Nationalists had banned during martial law.

The party was founded by human rights, democracy and independence activists. But Chen remains flexible on independence, said Shen Fu-hsiung, a Progressive Party lawmaker.

``Most of us think he's just trying to use this issue to his benefit,'' Shen said. ``Those in the heart of the independence movement have doubts about him.''

Shen acknowledged that from the broader perspective used by China and sometimes America, Chen's views and his referendum plans seem pro-independence.

Beijing is also suspicious of Chen because he won't call himself ``Chinese.'' He has yet to embrace China's goal of eventual unification, and continues to insist that Taiwanese voters should have a choice.

Chen's program to remake Taiwan also includes holding other referendums and rewriting the constitution. Many analysts agree things need to be done, but some question whether Chen is the person to do them.

Denny Roy of the Asia-Pacific Center for Security Studies in Hawaii noted that President Richard Nixon was a good man to restart U.S.-China relations because of his anti-communist background.

But Roy said he doubts Chen is the right person for the delicate tasks he wants to undertake. And Roy says the timing may not be the best.

``There must be a proper time and a proper place,'' he said.