Taiwanese voted in closely contested local polls on Saturday, after an election eve shooting killed one man and critically wounded the son of a former vice-president.

The mayoral elections pit President Ma Ying-jeou’s ruling Nationalists against the pro-independence Democratic Progressive Party in five large cities around the island.

The DPP were favoured in two constituencies in its southern heartland, Kaohsiung and Tainan, while the Nationalists had an edge in the central city of Taichung. Taipei in the north and its densely populated ring of suburbs, now known as Xinbei, were considered tossups.

The party that comes out best in the five cities, which together account for about 60 percent of Taiwan’s 23 million people, could have a big advantage heading into the next presidential election in March 2012.

That election will almost certainly feature Mr. Ma against a still-unnamed DPP candidate.

Mr. Ma, 60, favours expanding Taiwan’s already robust commercial ties with China, and if re-elected, could begin political talks with Beijing.

In contrast, the DPP wants to slow the pace of economic convergence across the 100-mile (160-kilometer) -wide Taiwan Strait and would likely close the door on political dialogue with the mainland, from which Taiwan split amid civil war in 1949. That might worry the United States, which has applauded Mr. Ma’s success in helping ease tensions in one of Asia’s traditional flash points.

Key questions hanging over Saturday’s poll were the performances of DPP Chairwoman Tsai Ing-wen in Xinbei and party veteran Su Tseng-chang in Taipei. The two are considered the DPP’s leading presidential candidates in 2012, and with an eye to that election, party members were looking to see which emerges from the voting in the stronger position.

Ms. Tsai, 54, was educated at Cornell Law School and the London School of Economics, and has considerable appeal among the centrist voters who put Mr. Ma over the top in 2008. By contrast, the 63-year-old Mr. Su is a grass-roots politician who can energize his party’s base and deflect the many barbs the Nationalists would throw his way in a presidential election campaign.

On Friday night, a man with a gangster background opened fire at a Nationalist rally in the Taipei suburb of Yung Ho, killing 29-year-old Huang Yun-sheng and critically wounding Lien Sheng-wen, son of former Vice President Lien Chan.

Lin Cheng-wei, 48, was taken into custody in connection with the attack. He reportedly told police that he had been targeting local city council candidate Chen Hung-yun, apparently because of a dispute between Mr. Chen and Lin’s father.

Acts of violence are unusual in election campaigns in Taiwan, which began a gradual transition from a one-party dictatorship to fully functioning democracy in the late 1980s. Violence by Taiwan’s gangs is also limited, though they exercise considerable political influence, particularly on county governments.

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