For more than a month, as the US has tangled with China, floated new terms for Middle East peace, watched North Korea test a ballistic missile and proposed an overhaul of ties with Russia, the State Department has been quiet.

Secretary of State Rex Tillerson made his debut on the international stage over two days in Europe last week -- and said less than 50 words in response to press questions, according to pool accounts. On Wednesday, he departs for Mexico -- a trip Americans first learned of from the Mexican press.

The State Department is responsible for explaining US foreign policy to the country and the world, and is the only agency outside of the White House that traditionally speaks publicly every day through a televised news conference. But since January 19, there has been no State Department briefing and, after Tillerson recently took the helm, there has been little in the way of communication about Foggy Bottom's priorities, schedules or policies.

Risks for a voiceless State Department

That silence may reflect ongoing upheaval in the Trump White House, administration power struggles, Tillerson's personal inclinations or the growing pains of a former ExxonMobil CEO adjusting to running a governmental organization. Regardless of the reason, diplomats, analysts and current and former State Department officials say there are risks if the dead air continues.

A voiceless State Department, they say, allows other countries to set the narrative about US policy and events, unsettling allies and potentially shortchanging US businesses, citizens and interests overseas.

"If you don't have the State Department engaging with the world in front of a camera, you lose the opportunity to shape the international interpretation of what US policy is," said Jeff Rathke, a former director of the State Department's press office now with the Center for Strategic and International Studies. "And you sacrifice an opportunity to steer the course of international events in a direction that's better for US interests than if you said and did nothing."

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In the three weeks since Tillerson's confirmation as the top US diplomat, Americans learned of the secretary's Tuesday phone call to Russian Foreign Minister Sergey Lavrov from Moscow's Foreign Ministry and of an earlier phone call to Saudi leaders from the Arab press. The State Department has refused to confirm many of the secretary's calls and meetings. His public schedule has been much lighter on details than other recent secretaries.

This retreat from public engagement coincides with the White House adopting an often-hostile approach to the press.

Many observers say there are structural factors at work, too, a central one being that it's not yet clear what the administration's foreign policy positions are -- in part because of presidential tweets and pronouncements that conflict with official statements. That makes it hard to respond to questions about those challenges.

The State Department didn't respond to requests for comment for this story.

Mixed messages stymie communication

To date, the President and his Cabinet have given mixed messages on issues like the US commitment to NATO, support for Asian allies, the approach to Russia and how to pursue peace between Israelis and Palestinians.

Last week, Vice President Mike Pence had to reassure NATO of US support and Defense Secretary James Mattis had to stress to Iraqis that the US would not seize its oil after Trump's intimations to the contrary, noted Jen Psaki, a former State Department spokeswoman.

The President's tweets and pronouncements mean "there is an unusual amount of confusion about how much is posturing and how much is a genuine policy," said P.J. Crowley, another former State Department spokesman. "We don't really know what the Trump foreign policy is."

One career State Department staffer, speaking on condition of anonymity to discuss internal operations, said that the agency feels paralyzed. That person described several layers of empty management positions between their section and the secretary.

"There's no guidance and the people I used to talk to are gone or they're being told not to say anything, so it's impossible to work," the staffer said.

The National Security Council, which guides the President on questions of foreign policy, also isn't fully staffed and has endured upheaval with the dismissal of former Lt. Gen. Michael Flynn less than a month into his tenure. Trump announced Flynn would be replaced by Lt. Gen. H.R. McMaster on Monday.

Major positions unstaffed

At the State Department, most leadership positions below Tillerson remain unfilled, including the deputy secretary, who operates as the secretary's No. 2; most under secretaries; the assistant secretaries who run regional bureaus; and their deputies.

Last month, the White House asked the department's top four management officials to step down as part of an effort to "clean house." Hostility between much of the Republican foreign policy establishment and the Trump administration complicates any attempts to fill those positions quickly.

There are also questions about where power over foreign policy decisions will rest and how much Trump's White House will try to dictate to State.

Trump's executive order temporarily barring entry into the United States for refugees and seven Muslim-majority nations came out of the White House with no warning to State, according to several State Department sources, which had to then execute the order. There has been no public reaction from Tillerson since the imposition of the controversial ban, which has earned vocal criticism from international leaders close to the United States.

"It's possible Tillerson is keeping his powder dry so he doesn't make enemies prematurely," said a former State Department official.

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The official said Cabinet members can try to sway an undecided president by speaking publicly -- a path Defense Secretary James Mattis has taken in stating his support for NATO and opposition to torture -- or they can keep quiet to see which way the wind blows. They can also try to get the President's ear and confidence by taking a lower profile.

But the official warned, "If you're not clearly drawing your line on an issue, no one is going to respect it."

There are costs to silence from the State Department, many current and former agency officials said, high among them the uncertainty it causes overseas.

"Communications is a tool of diplomacy," said Psaki, who served in the Obama administration and is now a CNN political commentator. "Foreign leaders, allies and adversaries, often read the State Department briefing, and it can be used as a vehicle for sending a message, lending support or condemning actions around the world."

A statement made during the briefing can also support US diplomats in the field working for a certain outcome.

State Department staff said that just recently they have been asked by higher-ups to start preparing guidance on policy issues to deliver to journalists at the daily briefings, though there's no sign yet they are set to restart.

A more cautious approach?

The agency's silence may also reflect Tillerson's more cautious approach to the media. On his trips to date, he has minimized the press traveling with him. At ExxonMobil, the only place he's ever worked, Tillerson reigned over a company not particularly open to the press, according to Steve Coll, author of "Private Empire," a 2012 book about the oil giant.

Tillerson never granted Coll an interview over his years of research for the book, according to the author. Speaking to NPR after the Texan's nomination, Coll said that the erstwhile oilman "has never confronted the kind of uncontrolled questioning and impertinent questioning that a secretary of state has to face -- not just all those ornery reporters in the back of your plane" but foreign service officers, foreign press and local activists, too.

"This is not Exxon's way," Coll continued. "You don't speak up and ... question the boss's fundamental assumptions in front of an audience."

Tillerson's performance at last week's G20 in Bonn offered a hint of his approach going forward. It's the kind of large gathering where leaders often engage in a form of foreign policy speed-dating, holding quick one-on-one meetings on the sidelines, each one marked by an appearance before the cameras and often a comment or two to the press. But Tillerson mostly stayed silent.

As TV crews and reporters were ushered out of the room during an appearance with UK Foreign Minister Boris Johnson, the British minister asked, "Are we still being recorded?"

Tillerson replied, "They never give up."