U.S. President Donald Trump (R) meets with Chinese Vice Premier Liu He (1st L) in the Oval Office of the White House in Washington, February 22, 2019. /VCG Photo.
Thus, whilst Trump undoubtedly desired the trade war to hurt China somewhat to gain concessions, he knew his limitations and risks well. He had no desire for a prolonged struggle. As a result, he opted for a strategy that was short, quick and of course offered Beijing the chance to negotiate from early on to de-escalate the situation, repeatedly having tweeted through the months beforehand that China "wanted to make a deal."
Such tactics are a modus operandi of Trump's, whereby he threatens irrational consequences on an opponent, threatens continued escalation and then offers the hand of negotiation to them when they fear a crisis. He then afterward claims "he won" – although on most occasions the eventual deal is often less than what people anticipate.
As a result, when the administration again talked tough over a "90-day window" for China to negotiate with the U.S. and offer economic concessions, this wasn't so much a threat as it was a negotiating pitch dressed up for domestic political consumption. Why? Because although Trump claimed it was only China demanding a deal, he most desperately wants one too.
Presented with the opportunity, he isn't going to jettison these talks and escalate the trade war further, for as noted the consequences will be economically disastrous. He wants a deal that allows him to say that he won, a deal that calms the uncertainty of markets and makes stocks boom, a deal which he can claim brings jobs back to America and in turn a deal which allows him to pitch success on his initial term for 2020. Do you think for any reason he would instead increase tariffs and sink the American economy in view of a presidential election?