Kuomintang presidential hopeful Ma Ying-jeou was busy yesterday trying to limit damage from the claim by his rivals that he had right of abode overseas.
As Frank Hsieh Chang-ting, the Democratic Progressive Party's candidate, continued to insist that his opponent's US green card was valid, Mr Ma repeated that the claim was groundless and a 'dirty joke' designed to undermine his legitimacy.
But last night some observers suggested that Theresa Shaheen - former chairwoman of the American Institute in Taiwan, the United States' de facto embassy in Taipei, and a known DPP supporter - could swing voters with comments on Mr Ma's green card status.
In a place where negative campaigning dominates elections over policy debate, this year's campaign was again marred by emotional attacks on the candidates' loyalty to the island.
The two camps have bickered over the technicalities of what constitutes residency in the United States, an issue that the DPP has attempted to link to being unfaithful to Taiwan.
Mr Ma, who first categorically denied holding a green card, admitted later that he was once granted permanent residency in the United States. But he argued that his green card was automatically invalidated when he moved to Taiwan in the 1980s, intending to settle down.
