TAIPEI, Taiwan - Taiwan's low-key presidential election campaign moved into high gear Saturday, as the three candidates jousted in a televised debate that could go a long way in determining the future of the incumbent's efforts to bring the democratic island closer to China.

President Ma Ying-jeou, from the ruling Nationalist Party, faced off against chief rival Tsai Ing-wen of the Democratic Progressive Party and veteran politician James Soong. Ma supporters fear that Soong, once a Nationalist stalwart, will split the votes of the China engagement camp and help Tsai's cause.

The 2 1/2-hour debate came exactly six weeks before some 15 million Taiwanese voters have the right to go to the polls to choose their leader. Opinion surveys give Ma a narrow lead over Tsai, with Soong trailing far behind.

Since taking office in May 2008, Ma has lowered tensions across the 100-mile- (160-kilometre-) wide Taiwan Strait to their lowest level since Taiwan and China split amid civil war in 1949, mostly through a series of ambitious commercial initiatives. He has left open the possibility of entering into political talks with Beijing if he is re-elected.

In his opening remarks at the debate, Ma tried to link Tsai with disgraced former President Chen Shui-bian, who is serving a lengthy prison term on corruption charges. Chen ruled Taiwan from 2000 to 2008.

"Do we want to go back to the eight bad years of the DPP?" Ma asked, describing the period as a time of rampant corruption and elevated tensions with China.

Tsai retorted that she was running for president in 2012, not 2008, and went on to accuse Ma of pursuing policies that had deepened Taiwan's economic inequality and opened the door for China to achieve its long-standing goal of bringing the democratic island under its sway.

She said that if elected she would reach out to all parties in Taiwan to form a "Taiwan consensus" to deal with China on a unified basis.

Ma refused to commit himself to such an approach, challenging Tsai to accept his own guiding China principle of "no independence, no unification and no war."

"I dare you to accept that," he said. "Particularly 'no independence."'

Ma was referring to a plank in the DPP constitution calling for formal independence, as opposed to the de facto sovereignty the island has enjoyed for the past 62 years.

Throughout her campaign, Tsai has tried to portray herself as a centrist, with little appetite for the hard-edged China policies Chen espoused during his time in office.

She continued along that track during the debate, especially by affirming that she wanted Taiwanese of all political stripes to deal with China together.

She also chided Ma repeatedly for his economic policies, which she alleged had made it difficult for ordinary Taiwanese to find good-paying, stable jobs and buy homes at affordable prices.