HONG KONG — China's reaction to the announcement by Washington of a large arms sales package to Taiwan suggests that, 20 months after Taiwan replaced hostility with cooperation in its dealings with the mainland, Beijing still believes it will ultimately need to use force to bring about unification.

The vociferous reaction, which includes not only suspending military-to-military relations with the United States but also sanctions against American companies producing and supplying these weapons, appears to suggest that Beijing does not appreciate the fact that the Obama administration saw to it that the weapons being sold are purely defensive in nature.

The bulk of the $6.4 billion package consists of Patriot missiles, Black Hawk helicopters and minesweepers, the purpose of which is to defend Taiwan. These weapons cannot be used to attack the mainland. These weapons were requested by the government of President Ma Ying-jeou.