WASHINGTON — The US Senate passed legislation Wednesday that would nullify US tariffs on Canada, just as US President Trump is engaged in trade talks in Asia as well as an increasingly bitter trade spat with US’s northern neighbour. The 50-46 tally was the latest in a series of votes this week to terminate the national emergencies that Trump has used to impose tariffs. While the resolutions won’t ultimately take effect, they have proven to be an effective way for Democrats to expose cracks between the president’s trade policy and Republican senators who have traditionally supported free trade arguments. …The Senate passed a similar resolution applying to Brazilian tariffs on Tuesday. …Vice-President JD Vance visited Republicans during a closed-door luncheon this week and also argued that they should steer clear of trade policy while the president negotiates deals.