Millions of tweets were flying furiously in the final days leading up to the 2016 US presidential election. And in closely fought battleground states that would prove key to Donald Trump’s victory, they were more likely than elsewhere in America to be spreading links to fake news and hyper-politicized content from Russian sources and WikiLeaks, according to new research published Thursday by Oxford University. Nationwide during this period, one polarizing story was typically shared on average for every one story produced by a professional news organization.