EXPLAINER: What's behind difficult Taiwan-China relations?

U.S. authorities say the gunman behind an attack on a church in southern California in which one person was killed and five injured was motivated by a hatred for Taiwan

TAIPEI, Taiwan -- U.S. authorities say the gunman behind an attack on a church in southern California in which one person was killed and five injured was motivated by a hatred for Taiwan.

Although born in Taiwan, David Chou nurtured a resentment toward the Taiwanese and reportedly had ties to a China-backed organization dedicated to furthering Beijing’s goal of annexing the self-governing island, by force if necessary.

That has revived questions about the complex and sometimes antagonistic relationship between the two sides, which separated amid civil war in 1949 and have followed very different paths since then — the one toward liberal democracy, the other toward increasingly repressive authoritarian rule under the Chinese Communist Party, which claims Taiwan, despite never having governed the island.

The following is a look at that background and the current state of affairs between the sides.