TAIPEI, Taiwan (CNN) -- Taiwan's opposition Nationalist Party won a landslide victory in legislative elections Saturday, giving a big boost to its policy of closer engagement with China two months before a presidential poll it now seems poised to win.
President Chen Shui-bian, who has been criticized for aggravating relations with China by promoting policies to formalize Taiwan's de facto independence, resigned as chairman of the ruling Democratic Progressive Party immediately after the extent of the defeat became clear.
"I should shoulder all responsibilities," Chen said. "I feel really apologetic and shamed."
His resignation does not affect his status as president.
With all votes counted, the official Central Election Commission said the Nationalists had won 81 seats in the 113-seat Legislature, against only 27 for the DPP, with four going to Nationalist-leaning independents, and one to a Nationalist satellite party.
Critics say Chen's China policies have allowed Taiwan's once-vibrant economy to lose competitiveness and have ratcheted up tension in the perennially edgy Taiwan Strait.
The Nationalists ruled a united China before 1949 and were the mainland communists' enemies in the civil war. But the party and Beijing have in recent years found common cause in their opposition to Chen.
Washington also has made it clear it finds Chen's policies toward Beijing dangerous and provocative -- particularly a planned referendum on Taiwanese membership in the United Nations, which appears designed to underscore the democratic island's political separateness from the communist mainland.
A March 22 presidential election to chose a successor to Chen, who must step down after eight years in office, pits the ruling DPP's Frank Hsieh against Ma Ying-jeou of the Nationalist Party. Recent opinion polls give Ma a 20-point lead, and Saturday's win by his party is likely to give the former Taipei mayor a further boost.
The DPP wants to formalize the independence Taiwan has had since an inconclusive civil war nearly 60 years ago -- but has held off out of fears that China would make good on its repeated threats to attack. In contrast, the Nationalists favor more active engagement with China and do not rule out eventual unification.
Speaking at Nationalist headquarters in Taipei, Ma relished his party's victory -- enough to give it a three-fourths majority together with the five allies -- but cautioned against overconfidence going into the presidential elections.
"We need to be cautious about the presidential poll, and hopefully we can win," he said. "With a Nationalist presidency and Nationalist-controlled legislature, we can push forward the reform expected by the Taiwanese people."
If the Nationalists do go on to recapture the presidency, they will be in a strong position to end years of deadlock between Taiwan's legislative and executive branches, and stabilize the island's rocky relations with China.
During Chen's two terms as president, the Nationalists used a slender legislative majority to block many of his policy initiatives, including the purchase of a multibillion-dollar package of American weapons. Also left stagnating have been negotiations to open direct air and shipping routes between Taiwan and China.
In the legislative campaign, Ma emphasized his message that Chen's reluctance to engage China inflamed tensions and hurt the island's economy -- one of the 20 largest in the world, and a major research and manufacturing base for the computer industry.
Ma also drew attention to American unhappiness with Chen's China policies. Twenty-nine years after it shifted recognition from Taipei to Beijing, the U.S. remains Taiwan's most important foreign partner, supplying it with the means to defend itself against any future Chinese attack.
In contrast to Ma, Hsieh maintained a relatively low profile in the legislative campaign, apparently because of his ambivalence over Chen's pro-independence stance.
Hsieh hews to the DPP's pro-independence line in principle, but has made it clear he rejects some of Chen's hard-line policies, including his moves to limit Taiwanese economic ties to the mainland.
He favors ditching Chen's requirement that Taiwanese companies limit investments in China to less 40 percent of their asset value. He also has indicated a willingness to expand direct charter flights across the 100 mile-wide Taiwan Strait.
Ma and the Nationalists go considerably farther. They want to remove the asset requirement altogether, and sanction regular flights between China and Taiwan.
China's government did not immediately react to the election results, but was likely to be pleased with the Nationalist victory.
In May 2005, then Nationalist Party Chairman Lien Chan made a historic visit to the mainland despite objections from Taiwan's government.
Lien, who now serves as the party's honorary chairman, met Hu in Beijing in the highest-level contact between the two rivals since they split. At the end of the meeting, they issued a joint pledge to promote an end to hostilities between the two sides.
"The election will have a positive impact, benefiting stability across the Taiwan Strait," said Yu Keli, head of the Taiwan Studies Institute, a Chinese government-backed think tank in Beijing. "The Taiwanese electorate has delivered a no-confidence vote on Chen Shui-bian." E-mail to a friend