Nic Robertson is CNN's international diplomatic editor. The opinions in this article belong to the author.

We should all worry when any court convicts bona fide journalists on trumped-up charges, and by all dependable accounts that's what happened in Myanmar this week.

Seasoned Reuters reporters Wa Lone and Kyaw Soe Oo were charged with violating the official secrets act and sentenced to seven years behind bars.

They'd been investigating a possible war crime -- the brutal massacre of Rohingya villagers by Myanmar's military.

More than 700,000 Rohingya, an ethnic minority group, have since fled the country. Many of them described brutal killings, rape and the indiscriminate burning of their villages.

Despite all the evidence, the government continues to deny it attacked unarmed Rohingya. Instead, it claims it has only targeted militia.

The two jailed reporters say they were set up by the police, surrounded and pressured into taking hold of documents they didn't want, then promptly arrested for having those documents by other officers waiting nearby.

They are far from the first journalists to face a backlash from Myanmar's authorities for their reporting. But the situation is worsening.

Late last year, Esther Htusan, a Pulitzer prize-winning Associated Press reporter, was forced to flee Myanmar following death threats. She believes she can't safely report from her own country.

So far this year, according to the Committee to Protect Journalists, 39 journalists have been killed around the world. Last year, the most recent for which the CPJ has reliable data, 262 journalists were imprisoned.

These figures alone, though, don't show the whole picture.

The ugly truth is that most of the dedicated, professional journalists killed or festering in jail for their reporting are local reporters -- natives of the oppressive regimes they are covering.

Outside of major conflicts, it is most often local reporters who have always borne the brunt of the hostilities, leading to jail or worse.

Unlike overseas reporters on assignment who can leave when the job is done, local reporters don't have the luxury of homes beyond bullets and the reach of the officials on whom they've been reporting.

It has long been this way, be it Beirut, Iraq or Afghanistan, where overseas reporters poured in for months at a time. But when the spotlight shifts, local reporters are left to continue alone.

What is different now is that we rely on these local reporters more than we have ever done before.

JUST WATCHED Wives of jailed reporters ask for mercy Replay More Videos ... MUST WATCH Wives of jailed reporters ask for mercy 02:03

Simply put, there are far fewer of the once ubiquitous overseas reporters around.

Many international newspapers and TV networks have closed all but a handful of overseas bureaus and rely increasingly on trusted networks of local professionals as a front line of substantial reporting.

Yes, social media has become a wonderful tool for alerting us to atrocities and less beastly developments. We have more video, more quickly than ever before. But the premium that we all want is accurate reliable information to go with all those pictures, to make sense of what we are seeing -- and hold those responsible to account.

We need someone reliable, responsible and familiar with the ethics of journalism there on the ground. Someone who knows the situation and can make it make sense with unbiased, accurate reporting.

That's the value of local reporters; it's also what makes them ready targets for autocratic regimes.

The reporters know their countries and their stories well, often have great sources and sometimes know who is hiding what and where.

Without a loud international outcry, governments that demonize and lock up good honest reporters for calling them to account will get the message they can scare all reporters into silence so they are free to violate whatever laws and norms they choose.

It was a continuous drumbeat of international outrage that ultimately helped Australian-Latvian journalist Peter Greste and, eventually, his local colleagues Mohamed Fahmy and Baher Mohamed get released after more than a year in Egyptian jail, accused of damaging national security.

That Greste was a western reporter on assignment helped his case.

There was often a bigger focus on him than his local colleagues. It helped amplify accusations leveled at the Egyptian government that his incarceration was unjust, and was ultimately telling that he, the foreigner, was released before Fahmy and Mohamed.

But even pulling off a release like that isn't as easy as it used to be.

We are in an era where full-throated protest to protect journalists is being drowned out by a narrative emanating from Washington, DC.

Those who would bully reporters are having a good time of it lately. They've got a new champion in their corner: US President Donald Trump.

His frequent lies and criticism of reporters who hold him to account has so muddied the waters, it seems that he has confused his own diplomats.

At a reception for reporters in London this week, the host, US Ambassador Woody Johnson, a friend of Trump, began his speech by welcoming the gathered journalists, praising their profession, commending their work and its value to society.

He pointed to the Second Amendment, in which he said these rights of freedom of speech and freedom of the press are enshrined.

Toward the end of the event, a kindly embassy staffer helpfully set the record straight, explaining that what Ambassador Johnson meant was the First Amendment, not the Second, which is the right to bear arms.

When a man of Ambassador Johnson's respected standing and stature inadvertently slips up on the very issue he finds himself -- because of Trump -- needing to make good, it suggests the "blame the messenger" bile flowing from the White House has become infectious.

This is not the time for muddled thinking. This is a time for clarity. Without clarity on what is right and what is wrong, those holding the Reuters reporters and the hundreds of other journalists around the world will think they can do what they want, surmising the most powerful man in world agrees with them.

They've got dirt. They want it swept under the carpet, not held up to the light.

Not "shooting the messenger" because you don't like the news, is one of the world's oldest diplomatic guarantees.

Secretary of State Mike Pompeo gets it. He's called for the release of the two Reuters reporters. But as long as the gangrenous attitude toward reporters continues oozing out of the White House, journalists will be at increased risk.

Trump isn't responsible for their incarceration, but he makes it a whole lot harder to win the argument that they should be released.

Without vigorous support for press freedom in the US and around the world, parts of the world will go dark to us -- and become even more grim for those who live and report there.