Try as it might to appease President Donald Trump, Canada remains a prized target in his trade wars and subject to the whiplash of his changes of heart. The giant North American neighbors are rushing to conclude a new trade accord by July 21 but the process is proving painful for Canada. Overnight Thursday, Trump threatened to slap a 35 percent tariff on imports from Canada starting August 1. But products complying with an existing accord, the United States-Mexico-Canada Agreement (USMCA), are expected to remain exempt, a Trump administration official and a source in Canada told AFP.