China ponders military intervention in Hong Kong - should the West mediate?

China says a Tiananmen square style military intervention in Hong Kong would be a last recourse. Knowing what happened at Tiananmen square, should civil democracies intervene?

https://www.bloomberg.com/news/articles/2019-08-25/china-signals-intervention-as-hong-kong-s-protests-intensify

https://en.wikipedia.org/wiki/1989_Tiananmen_Square_protests