Peter Baker and Michael D. Shear in NYT:
"With a petulant tweetstorm from Air Force One, Mr. Trump all but blew up the Group of 7 nations that the United States has led for more than four decades and essentially declared open political war on America’s closest neighbor."
Read the article here.
There is a distinction between a petulant tweetstorm and open political war. Given the muted official response from other members of the G-7, or G-6+1 as it has been called as well, the open political war is mainly entertainment.
Entertainment that is benefiting Putin, but that's old news.