Having previously expressed her opinions on Donald Trump, including famously described the presidential candidate as worse than Voldemort in a tweet, Rowling has now moved to defend his right to speak his mind, saying "his freedom to speak protects my freedom to call him a bigot".
"Intolerance of alternative viewpoints is spreading to places that make me, a moderate and a liberal, most uncomfortable," Rowling said.
"Only last year, we saw an online petition to ban Donald Trump from entry to the U.K. It garnered half a million signatures.
"I find almost everything that Mr. Trump says objectionable. I consider him offensive and bigoted.
"But he has my full support to come to my country and be offensive and bigoted there. His freedom to speak protects my freedom to call him a bigot.
"His freedom guarantees mine.
"Unless we take that absolute position without caveats or apologies, we have set foot upon a road with only one destination,.
"If my offended feelings can justify a travel ban on Donald Trump, I have no moral ground on which to argue that those offended by feminism or the fight for transgender rights or universal suffrage should not oppress campaigners for those causes.
"If you seek the removal of freedoms from an opponent simply on the grounds that they have offended you, you have crossed the line to stand alongside tyrants who imprison, torture, and kill on exactly the same justification."
Rowling also accepted an award at the PEN Gala for her humanitarian work.