A newspaper in Arizona has reportedly received death threats for its first-time endorsement of a Democratic candidate in more than a century.

The threats to the Arizona Republic editorial board included: “You’re dead. Watch your back”, and “You should be put in front of a firing squad as a traitor”.

In an op-ed, Mi-Ai Parrish, president the newspaper and Republic Media, wrote that they decided to support Hillary Clinton, and it was the first time they had endorsed a Democrat in 125 years.

“In piece after piece, we made it clear that his principles weren’t conservative. They were bad for the party, bad for Arizona, dangerous for America,” she wrote.

Instead of endorsing no candidate, they decided to make the “unpopular” choice of supporting Ms Clinton.

“We chose patriotism over party. We endorsed the Democrat,” she wrote.

”And then the reaction started pouring in. Threats against our business. Threats against our people.”

She and her staff had been called “un-American”, “hacks”, “losers with no purpose” and their young people who sell subscriptions had been bullied and "screamed at and spat on".

She highlighted the late reporter Don Bolles, who was blown up in his car 40 years ago “for doing his job”, and he died 12 days later. Readers said their late editor, Gene Pulliam, would be “spinning in his grave” for the Democratic endorsement, but Ms Parrish said that the editor’s wife, Nina, cried by Bolles’ hospital bedside.

“The Pulliams understood that free speech, and a free press, come at a cost,” she wrote.

Ms Parrish’s family emigrated from Korea to the US after World War II, and her mother taught her not to take freedom of speech or the right to vote for granted.

She added that her reporters worked hard to ensure their coverage was fair and that every morning they walked past an inscription of the First Amendment on the office wall.