Today, they're on par with the United States. But, if this trend continues – which it will – their economy will be triple the size of the US economy in 20 years.
Not just a trade war, but a shooting war with the Chinese seems inevitable. Because when tensions build up between states they eventually fight with each other. China is the major rising power. It's got four times the US population, it's soon going to be more economically powerful, and it's going to reach military parity. It's of a different culture than the US. The US government may figure it's best to take them out while the balance still favors them. It's a bit like the situation was with the USSR in the '80s. They could see they were going into decline, and some Soviet generals figured it was "now or never" for a successful war. Fortunately they collapsed first.
The Chinese don't like seeing US aircraft carriers off their coast any more than we would like to see Chinese aircraft carriers in the Gulf of Mexico or off Santa Catalina Island.