President Donald Trump says he is on a mission to save American industrial jobs, cut China's trade surplus with the US and strike back at what he says have been decades of theft of intellectual property by Chinese businesses. Under past US presidents, the preferred trade tool was filing cases at the World Trade Organization's Dispute Settlement Body, where they can take three to five years to fully resolve. Trump has dipped into a different, much more immediate arsenal of weapons, most of them under the rationale that trade affects national security.