It would put to bed the idea that the PRC and ROC are still involved in a civil war that’s just on pause. If Taiwan said “The civil war’s done, you won, we only claim this island now”, China could still claim that the island is theirs and Taiwan is an occupier, but they couldn’t pretend that the civil war is still ongoing. It could also give other countries an excuse to have normal diplomatic relations with Taiwan. Instead of having to choose between the ROC or the PRC as the legitimate government of China, they could say that the PRC is the legitimate government of China, but that Taiwan is a breakaway region that gained independence back in 1949, and that they recognize Taiwan as a country too… but only as the legitimate government of that one small island.
As for whether it would make an invasion more or less likely, who knows. It probably wouldn’t change anything. China has to know that if they ever invaded it would be an extremely costly invasion, and anything of value in Taiwan would likely be destroyed. Invasion would be devastating to Taiwan’s economy, and terrible if not devastating to China’s economy. The only reason to do it is political. Theoretically it could be something a weak central government could do to make the people feel patriotic and to make the government seem strong. But, that might backfire and they might look weak and people could lose faith and/or stop fearing them.
What would Taiwan gain by doing this? It’s not obvious to me whether declaring independence would make the PRC-invasion scenario more or less likely.
It would put to bed the idea that the PRC and ROC are still involved in a civil war that’s just on pause. If Taiwan said “The civil war’s done, you won, we only claim this island now”, China could still claim that the island is theirs and Taiwan is an occupier, but they couldn’t pretend that the civil war is still ongoing. It could also give other countries an excuse to have normal diplomatic relations with Taiwan. Instead of having to choose between the ROC or the PRC as the legitimate government of China, they could say that the PRC is the legitimate government of China, but that Taiwan is a breakaway region that gained independence back in 1949, and that they recognize Taiwan as a country too… but only as the legitimate government of that one small island.
As for whether it would make an invasion more or less likely, who knows. It probably wouldn’t change anything. China has to know that if they ever invaded it would be an extremely costly invasion, and anything of value in Taiwan would likely be destroyed. Invasion would be devastating to Taiwan’s economy, and terrible if not devastating to China’s economy. The only reason to do it is political. Theoretically it could be something a weak central government could do to make the people feel patriotic and to make the government seem strong. But, that might backfire and they might look weak and people could lose faith and/or stop fearing them.