President Chen Shui-bian (陳水扁) said yesterday he would resign immediately if Chinese National-ist Party (KMT) presidential candidate Ma Ying-jeou (馬英九) could provide legal documents proving that his green card had been invalidated years ago.
Chen put his presidency at stake in an interview with Formosa TV last night.
If Ma's green card remains valid, he should give it up by completing all the legal procedures, the president said.
In a televised campaign platform presentation on Friday, Democratic Progressive Party presidential candidate Frank Hsieh (謝長廷) also said he was willing to apologize and withdraw from the race if Ma could prove that his green card was invalidated 20 years ago.
Ma's US green card status has been a subject of controversy and attacks by Hsieh's campaign.
When Hsieh first raised the issue in late January, Ma initially responded by saying he did not have a green card, but later conceded that he possessed one in 1977 to help him obtain student loans and employment after graduation. He claimed it was automatically invalidated in 1985 when he applied for a visa to travel to the US.
Hsieh said Ma has yet to provide proof to back his claims, adding that he believed Ma still holds a valid green card because he never completed an I-407 form to relinquish his permanent residency nor has a US immigration court invalidated his card.