Donald Trump, the US President, tweeted that he would not approve the commitment of the G7 conference.
Reuters: Trump torpedoes G7 effort to ease trade spat, threatens auto tariffs
Trump participated in the G7 discussion but left early for attending the summit with North Korea. At last, G7 made a declaration in which easing the barrier against free trade is one of the missions in the international collaboration.
Trump has an ideology "America Frist" as the leader of the US. He wants to protect the advantage of domestic industries. Therefore, he is willing to keep a high level of tariff. Thus, he cannot accept the global commitment to lower the tariff because of his stance.
On the other hand, the US is gradually becoming isolated in the international society. Justin Trudeau, the Prime Minister of Canada, seems to be ready to confront Trump's challenge.