TAIPEI, Taiwan (AP) — Taiwan’s main opposition Nationalist Party announced its vice presidential candidate Friday as hopes for a cross-party alliance to challenge the ruling Democratic Progressive Party have fractured and relations with China remain tense.

Hou Yu-ih said former legislator and Cabinet member Chao Shao-kang would be his running mate in the January polls. Chao had led a breakaway faction of Nationalist politicians who established the New Party in the 1990s, but has since returned the Nationalist camp as the DPP has held on to power in both the presidential office and the legislature.

The announcement comes days after the DPP announced that its presidential candidate, serving vice president William Lai, had recruited former de-facto ambassador to the U.S. Bi-khim Hsiao as his running mate. The Lai-Hsiao ticket is favored to win in the January polls, taking over from incumbent President Tsai Ing-wen, who is limited to two terms.

The parties are largely divided by their attitudes toward China, which claims Taiwan as its own territory to be annexed possibly by force. The Nationalists, also known as the Kuomintang or KMT, agree the sides are part of the same country — albeit under separate governments — while the DPP holds that Taiwan is effectively an independent nation with no need to make a formal declaration that could draw greater military, economic and diplomatic pressure from China.

The Nationalists and the smaller Taiwan People’s Party were expected to unveil an agreed-upon candidate, but could not come to agreement. The TPP’s candidate Ko Wen-je, the former mayor of the capital Taipei, also announced his running mate, former deputy mayor Cynthia Wu Hsin-ying.

The outcome of the election could have major effects on relations between China and the United States, which is bound by its own laws to provide Taiwan with the weapons it needs to defend itself. Differences over Taiwan are a major flashpoint in U.S.-China relations.

A fourth candidate, Terry Gou, the billionaire founder of tech giant Foxconn, has also joined the race, but there was no immediate word on his registering a running mate.

Despite the failure to form a united front, Nationalist General Secretary Chu Li-lun called for voters opposed to the DPP to join behind a single candidate.

The DPP have favored closer ties with the United States as a way to preserve Taiwan’s separate status from China, which has cut off almost all contacts with Tsai’s government over its refusal to agree that Taiwan is an inherent part of China.

The Nationalists said that friendlier ties with China were a better approach, and the TPP, a relative newcomer to the political scene, likewise backed building amicable relations and mutual prosperity with China.

Tsai’s refusal to bow to China’s demands have led to threatening military drills in the seas and skies around Taiwan by the Chinese military. The U.S., in turn, has countered by pledging support for Taiwan and maintaining arms sales to its military, further angering China. Taiwan has also invested heavily in military

Separated by 160 kilometers (100 miles) of ocean, Taiwan and China split amid the civil war that brought the Communists to power in China in 1949, with the losing Nationalists setting up their own government in Taiwan. which previously had been a Japanese province.