特朗普征收关税的理由部分集中在他认为北部边境的安全不足，无法阻止非法毒品和移民的流动。加拿大在去年12月做出回应，承诺斥资9亿美元购买无人机、直升机和监视塔，并在5525英里的边境部署更多特工。

Trump said he would impose 25 percent tariffs and various sanctions on Colombia after the South American country refused to ...