1) The 70 year rule says that no communist party has ruled over a nation for more than 70 years including that of the former Soviet Union. That 70 year glass ceiling for the Communist Party of China arrives in the fall of 2019. Securing the Party's grip on the levers of power past 2019 and into 2020 would signal an unprecedented victory for the Party and help secure his eternal rule.
2) Xi Jin Ping has pledged and vowed to "reunify" the "renegade province" of Taiwan back to China during his tenure and secret papers that were leaked out of Beijing last year revealed that the goal was to do so by 2020.
3) Accomplishing all these things before the 2020 U.S. presidential election is of great necessity particularly if a President Trump is reelected and continues to stand in China's way.