Already on the international front, China is in trouble. The pro-China KMT party in Taiwan may suffer greatly in the next election because of what's going on in HK now (https://www.scmp.com/news/china/politics/article/3037040/tai...), making China's aggressive demands for forced unification even more unlikely in the medium term. This week, the U.S. Senate unanimously passed a HK rights bill (https://www.reuters.com/article/us-hongkong-protests-usa/us-...) that, if it becomes law, will put China through an annual review, which will further erode the Sino-U.S. relationship for years to come. There have been calls for a boycott of the 2022 Olympics in Beijing which seems fringey now, but won't be if China sends in the troops.
There's also the internal question. Ordinary people in China are getting censored news, but some of the raw information about what's going on is getting through via social media. What does this mean for sentiment in Cantonese speaking areas of southern China, or for areas of China where provincial officials are resented for unjust or unfair treatment of citizens?