Press freedom is essential to democracy. You cannot have one without the other. That is a statement of fact, not a boast. It follows that the activity specifically created to exercise press freedom – namely, journalism – has to be nurtured and protected.

Yet in countries across the world, journalism is under persistent attack. In Iraq and Syria, journalists have long been unable to operate freely. Nor can they do so in the countries fighting a proxy war in that region, Iran and Saudi Arabia.

In neighbouring Turkey, well before the latest military coup, press freedom was under severe pressure. During administrations headed by Recep Tayyip Erdoğan, the country became the greatest jailer of journalists.

During the coup, it emerges that it blocked social media, a further example of its intolerance of free expression.

In Egypt, five years on from the overthrow of Mubarak, successive governments have sought to control the media by imprisoning journalists and imposing measures designed to restrict press freedom.

If I was to continue with a global tour of countries where press freedom does not exist, that list would lengthen considerably. But we must see beyond the usual suspects, looking much closer to home, to understand the real crisis of press freedom and its implications for democracy.

Most notably, consider the current situation in the United States, the home of the brave and the land of the free. An unprecedentedly divisive presidential election has resulted in a new climate of hostility towards journalists.

It has become so worrying that scores of writers have signed a petition organised by PEN America calling on the US presidential candidates to “uphold freedom of the press and end intimidation toward journalists”.

During the presidential campaign, said the petition, “we have seen candidates and their supporters launch vicious insults and threats at journalists — excluding reporters and media outlets from access to campaigns, making hostile remarks and gestures toward individual journalists, and showing indifference toward harassment from supporters.”

The signatories include Martin Amis, Margaret Atwood, Jay McInerney, Judy Blume and Janet Malcolm. And the petition is supported by press freedom watchdogs such as the Committee to Protect Journalists and Reporters Without Borders (RSF).

It will delivered today to the Republican and Democratic national committees ahead of the conventions that are expected to see Donald Trump and Hillary Clinton endorsed as the parties’ candidates.

PEN America’s executive director, Suzanne Nossel, told the Politico website of “threats directed at journalists” and “remarks about the tightening of libel and defamation laws.”

PEN’s concern is echoed by the White House Correspondents Association. In an article published by USA Today on Thursday, its outgoing and incoming and presidents (the Wall Street Journal’s Carol Lee and Jeff Mason of Reuters, respectively), registered their “alarm” about the candidates’ restrictions on the journalists.

There was, arguably, an element of special pleading in their polemic. But they made relevant points about reporters being banned from events “because the candidate doesn’t like a story they have written or broadcast” and the refusal to answer questions at press conferences.

Such actions, said the writers, deprive the American people “of hearing from their potential commander-in-chief in a format that is critical to ensuring he or she is accountable for policy positions and official acts.”

Note also the treatment of journalists covering #blacklivesmatter protests over the weekend. Three were arrested in Baton Rouge for “obstructing the highway” and two others were briefly detained in Rochester, New York.

This followed last year’s arrests of several journalists in Baltimore after police had shot dead a black man, Freddie Gray.

As Delphine Halgand, the US director of RSF, remarked: “The United States, the country of the first amendment, cannot afford to keep journalists from reporting by arresting them for merely covering protests against police brutality.”

Indeed, it cannot. If press freedom cannot be safeguarded within democracies then it is no wonder that its complaints about lack of press freedom elsewhere sound so hollow. It is essential for democratic countries to protect press freedom in their own backyards