BEIJING (AP) — In a rare public expression of dissent in China, a well-known political commentator and a prominent businesswoman have penned open letters urging lawmakers to reject a plan that would allow President Xi Jinping to rule indefinitely.

Their impassioned statements on a popular messaging app were circulated widely after the ruling Communist Party announced a proposal Sunday to amend the constitution to scrap term limits on the president and vice president.

In a statement Monday on WeChat to Beijing's members of China's rubber-stamp parliament, Li Datong, a former editor for the stat...