Washington CNN  — 

Secretary of State Rex Tillerson will mark the service and sacrifice of America’s diplomats on Friday in a what’s expected to be a poignant ceremony in front of the State Department’s memorial wall.

It comes just days after he launched an ambitious project to restructure – and greatly pare back – the agency.

As Tillerson’s review gets underway, the staff he is set to address Friday is already grappling with the implications of a widespread leadership vacuum in the senior tiers of the great majority of its bureaus and at a third of its embassies.

Nearly all the senior positions under Tillerson are vacant or filled on an acting basis by career officials who were not chosen by the President and not confirmed by the Senate – and therefore are due to soon be replaced.

In addition to one out of every three ambassadorships being empty, five of the six undersecretary positions and 22 of the 24 assistant secretary positions are also unmanned.

RELATED: Tillerson asks State Department employees to weigh in on cuts

Amid an avalanche of urgent foreign crises, policy makers, diplomats and analysts are expressing concerns about the State Department’s ability to communicate its priorities abroad and settle conflicts within its own bureaucratic structure.

The vacancies are even of concern to Republicans like Mike Rogers, a former congressman who served for five years as chairman of the House Intelligence Committee and is now a CNN contributor. He recently wrote in The Washington Post that the administration is managing foreign crises “with one hand tied behind its back because it lacks a fully staffed State Department.”

Nearly 100 individuals need to be nominated and confirmed by the Senate for these senior leadership positions overseeing every region of the globe and issues ranging from arms control to energy to diplomatic security to much, much more.

Even under ideal circumstances, that nomination process can easily take four to six months. But in the first year of a new administration – especially when a new political party takes the helm – it can quickly become significantly more bogged down.

“This administration is particularly chaotic, but the first year of every administration is chaotic,” said Ronald Neumann, a three-time US ambassador who currently serves as the president of the American Academy of Diplomacy.

New administrations often want to make sweeping policy changes, ousting the senior political appointees from the last administration in favor of their own supporters as part of that transition.

But making broad changes, according to Neumann, can be challenging for incoming officials who don’t have the institutional knowledge to implement them.

“They think you can just give an order and march,” he said. “It’s kind of like trying to steer a ship with a compass and no map.”

While Tillerson is hardly the first secretary of state to grapple with high-level vacancies at the start of his tenure, there are a couple ways the Trump administration’s approach has been unique.

Most notably, in the early weeks of the administration the Trump White House asked for the resignations of several senior career officials who had served both Republican and Democratic presidents and, in some cases, had expected to stay on in the new administration.

The Trump administration also took a hard line with politically appointed ambassadors nominated by his predecessor.

Traditionally, ambassadors in this category – often influential members of the previous president’s party or wealthy party donors – submit letters of resignation at the end of an administration. But often, incoming presidents will grant short-term extensions on a case-by-case basis. Trump chose to grant only one such exemption, for the ambassador to Costa Rica.

Vacant ambassadorships currently include strong allies, like Canada, Germany and the United Kingdom, as well as partner countries in the anti-ISIS coalition, like Jordan and Saudi Arabia.

The Trump administration has formally nominated ambassadors to the United Nations, Israel, China, Japan and New Zealand. Only the first two have been confirmed.

The administration has also re-nominated two career personnel – to Senegal and the Republic of Congo – who were initially nominated under President Barack Obama but not confirmed before the end of this administration.

“It isn’t critical to have every ambassadorship filled,” said Larry Sabato, Director of the University of Virginia Center for Politics. “But you want all the major ones filled as quickly as possible, if for no other reason than that, in those countries where there’s no American ambassador, it looks as though they’re low priority. They interpret it that way.”

Other key roles are also vacant or filled with holdovers. For instance, special envoys for both Syria and North Korea remain in place, but come from the previous administration.

RELATED: White House says State Department responsible for vacancies

Special Envoy for Syria Michael Ratney is also concurrently serving as a deputy assistant secretary in charge of the Palestinian portfolio because of the shortage of senior officials in the department’s Bureau of Near Eastern Affairs.

Deputy Spokesman Mark Toner insisted in a State Department briefing last week, however, that the empty positions at the department “are not ‘vacancies.’ “

“There are senior State Department officials serving in acting capacities, but these folks are seasoned veterans of the foreign service and seasoned diplomats,” he added. “I know many of them personally and I can speak and attest to their expertise and their professionalism.”