Washington CNN  — 

The Trump administration’s decision to drop plans to nominate academic Victor Cha as ambassador to South Korea – which prompted him to issue a direct challenge to the White House over its consideration of a pre-emptive strike against North Korea – is the latest decision that leaves a crucial diplomatic post in limbo.

As the post sits empty, so do dozens of other important ambassadorships.

Numerous countries do not currently have a Senate-confirmed US ambassador in place, including key allies alike Jordan, Turkey, Saudi Arabia.

Of the vacant posts, around 30 are still awaiting a nominee, while seven others have nominees pending confirmation.

President Donald Trump also has yet to nominate people for senior roles at many international organizations, and to oversee important regional and issue-based bureaus.

As his administration grapples with an increasingly aggressive North Korea, Trump lacks not only a permanent ambassador to South Korea, but also a permanent Undersecretary for Arms Control and International Security Affairs, and a permanent Assistant Secretary for East Asian and Pacific Affairs. Candidates have been nominated for both positions, but are still awaiting confirmation by the Senate.

As of Wednesday, two of the agency’s six undersecretary positions await nominees, while another two have nominees who have not yet been confirmed. Most of the State Department’s 24 assistant secretary positions are vacant as well, or held by an acting official.

While senior acting officials hold the reins in these important jobs, they are not permanent appointees, and are limited in how long they can hold the roles.

Federal law allows these temporary office-holders to stay in these open jobs for, at most, 300 days. But more than 370 days have elapsed since the start of the Trump administration and acting officials in the State Department are starting to hit that limit, making presidential nominations more important than ever.

One of the longest-pending ambassadorial nominees is K.T. McFarland, Trump’s pick as ambassador to Singapore, who is facing an uphill battle to be confirmed as she faces tough questions about her knowledge of communications between former national security adviser Michael Flynn and former Russian ambassador to the US Sergey Kislyak.

Meanwhile, several ambassadors have retired or plan to retire in the coming months. They include John Feeley, the US ambassador to Panama who announced he will be stepping down in March over disagreements with the administration.

Trump has been slower than his recent predecessors to nominate State Department personnel. He made 81 nominations for the State Department and US Mission to the United Nations in his first year in office, compared to 128 made by then-President Barack Obama in his first year.