HISTORY CASTS a long shadow over relations between the Chinese Communist Party and the Kuomintang (KMT), which ruled China until Mao Zedong’s Red Army forced it to flee to Taiwan in 1949. The two parties remained sworn enemies for decades afterwards as the KMT fortified its island refuge with American weapons. Only in 1991, as Taiwan democratised, did the KMT formally renounce its goal to retake China by force. And yet, in one of the stranger ironies of present-day geopolitics, China now sees the KMT—the biggest opposition party in Taiwan’s current parliament—as its best hope of peacefully uniting the island with the mainland.

Hence the hoopla surrounding a planned visit to China by Cheng Li-wun, the new KMT chairwoman, between April 7th and 12th. Ms Cheng is expected to meet China’s president, Xi Jinping, on the first visit there by a KMT leader in a decade. But her trip is not only dividing public opinion in Taiwan. It is deepening American doubts about Ms Cheng, who is blocking the government’s proposed $40bn increase in defence spending, mostly on American weapons. And it is widening a rift between Ms Cheng and a rival KMT faction that leans closer to America.

The timing makes the visit even more controversial. It comes about a month before a planned summit between Mr Xi and his American counterpart, Donald Trump. At it, Mr Xi is expected to try to persuade Mr Trump to dilute America’s verbal support for Taiwan and to delay or reduce American arms sales. Chinese officials have already tried to drive a wedge between Mr Trump and Taiwan’s president, Lai Ching-te, by portraying him as a separatist who could drag America into a war over the island. Mr Xi may try to argue that Ms Cheng, whose party and its allies currently control parliament, represent the majority of Taiwan’s people.

Much therefore depends on what Ms Cheng says during her visit to Shanghai, Nanjing and Beijing, and especially in her meeting with Mr Xi, which is expected to take place on April 10th. She may avoid expressing views on unification given the sensitivity of the subject back home. But if she repeats her frequent assertions that Taiwanese people are Chinese or that both sides of the Taiwan Strait are part of “one China”, mainland authorities are likely to exploit those comments in their propaganda and diplomacy. For Mr Xi, “by shaping this kind of atmosphere and manipulating public perception, the main goal is of course to influence President Trump,” says Chen Shih-min of National Taiwan University.

American angst was evident when a bipartisan delegation of its senators visited Taiwan at the end of March. They urged Taiwan’s political parties to come together to approve the increase in military spending. “That deterrence is the most important thing we can build on to prevent a conflict that would be devastating for the region and for the world,” said Jeanne Shaheen, a Democratic Party senator and co-leader of the group. Asked about Ms Cheng’s trip, she said dialogue was a “good thing” but China should be open to talking to other Taiwanese politicians.

Taiwan’s government, meanwhile, warned the KMT not to fall for China’s “divide-and-rule strategy”. Meeting China’s leadership would not induce it to abandon its goal of annexing Taiwan, while accepting China’s political narratives would “deepen divisions within Taiwan, undermine public morale and send the wrong message to the international community”, said Chiu Chui-cheng, the head of Taiwan’s Mainland Affairs Council. He also cited a Taiwanese law that forbids unauthorised people from making political agreements with China.

When the KMT was last in power, from 2008 to 2016, China expanded trade, tourism and transport links with Taiwan. But it shuns President Lai’s Democratic Progressive Party (DPP), which maintains that Taiwan is already an independent sovereign nation. China particularly resents the DPP’s rejection of the “1992 consensus” whereby China and Taiwan’s KMT government agreed that both sides of the Taiwan Strait are part of “one China” while allowing for different interpretations of what that means.

Mr Xi is thus hoping that the KMT and its allies will dominate local elections in Taiwan in November and win the next presidential poll in 2028. If they do regain power, Mr Xi might be able to revive economic and other exchanges enough to convince him that peaceful unification can still be achieved, if not within his own lifetime, then by the centenary of Communist rule in 2049, his deadline for “national rejuvenation”. Another DPP victory, however, could cause him to lose patience and turn to military options.

China, like Ms Cheng, portrays her visit as a peace mission. Zhang Han, a spokeswoman for the mainland’s Taiwan Affairs Office, said that enhanced dialogue with the KMT would advance the “peaceful development” of relations across the Taiwan Strait. Chinese scholars suggested that it would reinforce a shared commitment to the 1992 consensus and opposition to Taiwan’s independence. Ms Cheng’s visit to Nanjing, once the KMT government’s capital, would highlight the party’s historic links to the mainland, while her trip to Shanghai would showcase economic opportunities, said Wang Yong of Peking University.

The snag for both Mr Xi and Ms Cheng is that closer cross-strait ties hold little appeal for many Taiwanese voters. Opinion polls consistently show that a majority of them distrust China’s government, have little appetite for unification and consider themselves Taiwanese rather than Chinese. They also suggest that a majority back the proposed increase in defence spending. One poll conducted in March showed that 56% thought that the disadvantages of Ms Cheng meeting Mr Xi outweighed the advantages.

Ms Cheng believes that such views will change as people become more worried about the risk of war and less sure of America’s security guarantees under Mr Trump. Many people on the island “feel that America is abandoning Taiwan”, she told The Economist in January. But her strategy is divisive even within her own party. Some prominent KMT figures worry that her remarks about Chinese identity, her outreach to Mr Xi and her position on military spending may cost the party votes in the coming elections.

One of her main rivals is Lu Shiow-yen, the mayor of Taichung city and a frontrunner to be the KMT’s presidential candidate in 2028. (The nominee is usually chosen through primaries or by committee a few months before the election.) Ms Lu visited America in March and spent much of her time there trying to convince American politicians and officials that the KMT was not opposed to increasing military spending. The KMT has proposed a much smaller supplementary defence budget of about $12bn. But on March 30th Ms Lu proposed a bigger rise of between $25bn and $31bn (which Mrs Shaheen noted approvingly), though it is still smaller than the one proposed by the DPP-led government.

That tussle is now seen as part of a broader struggle between one KMT faction that favours closer ties with China and another that leans more towards America, says Hsiao Yi-ching of Taiwan’s National Chengchi University. The challenge for Ms Cheng, he says, is to stress the need for peace and dialogue without appearing to be subservient or to echo China’s talking points. The civil war on the mainland may be long over. But the one within the KMT’s own ranks will shape Taiwan’s future.