A public battle between social media platform Twitter and Donald Trump, may perhaps lead to a redefinition of freedom of expression in America, and also affect the right of social media platforms to moderate content. On Wednesday, Twitter fact-checked Mr Trump when he tweeted to his 80 million-plus followers that mail-order balloting was “substantially fraudulent” and mail-in ballots would lead to a “rigged election”. Twitter placed a fact-check warning under two tweets: “Get the facts about mail-in ballots.” These led to a link debunking Mr Trump’s claims as false. (He has himself voted by mail.) Mr Trump responded with a