Hundreds of newspapers across the US have banded together to push back against Donald Trump's attacks on journalists, whom he has often attacked as "fake news" and "an enemy of the people."  Newsrooms ranging in size and political spectrum...published editorials arguing that the president's frequent assaults on the media were unjustified and that journalists were "not the enemy."  The list of participating newsrooms totaled more than 350..., according to the Boston Globe, which launched the initiative...The opinions of newsroom editorial boards are typically separate from their news coverage.  The Globe...noted...that its opinion pages "are completely separate from the news operation," and that the editors of its opinion pages and newsroom "do not coordinate decisions on coverage."  Trump appeared to acknowledge the campaign...saying in a series of tweets that the "fake news media is the opposition party" and accusing journalists of "pushing a political agenda or just plain trying to hurt people."  The newsrooms' editorials come two weeks after an Ipsos poll found that almost a third of Americans agreed with the sentence: "The news media is the enemy of the American people."...That trend has deepened under Trump, who has routinely berated newspapers and journalists who published unflattering news about him as "fake news," both on Twitter and in speeches...Some newsrooms have refused to join the Globe's campaign...