Update: An error in the earlier version of this article caused some confirmations to be double-counted in the nominated-but-not-yet-confirmed tally. The charts have been updated.

President Trump has a major staffing problem. He has been president for five months, and yet his agencies are severely understaffed at the highest levels. And, no, it's not all Senate Democrats' fault.

In the all-important State Department, the Senate has confirmed only one-third of positions that President Barack Obama had at the same point in his presidency. And that's not because, as Trump claims, Senate Democrats are blocking his nominees. (Democrats can slow-walk committee hearings, but they can't actually block votes.) Trump is way behind other recent presidents in nominating people for the Senate to vote on.

The State Department is more settled than other major federal agencies. In more than half of Trump’s 15 primary executive departments, only one Trump appointee has been confirmed: the secretary who heads the agency.

This comes from new data compiled by the Partnership for Public Service for The Post, which reveals that other transitions were much further along at this point. And maybe that's how Trump wants it.

The numbers, gathered as of Friday, show Trump has taken action on about 120 Senate confirmable positions at the major departments. His three immediate predecessors had all nominated around 200 or more by this point.

For all this tweeting about Democratic obstructionists, Trump may be trying to play catch-up now. As of June, he's started nominating 20 high-level positions every week. There's actually a law that says Trump must act within a certain amount of time or risk having to leave the positions empty — without a temporary official filling in — giving even more duties to the heads of the agencies.

While most of the positions are not sitting vacant — civil servants or holdovers from the previous administration stay on temporarily — the backlog is leaving a cloud hanging over the federal government and making it difficult to accomplish other administration priorities, say some experts.

Max Stier, the head of the organization that is collecting the data, warned that a lack of permanent appointees to head the agencies can hamper the efficiency of government.

“It creates a great deal of uncertainty and, ultimately, it diminishes the ability of government to do its job as well as it could,” he said. Stier said vacancies at national security-related agencies (State, Defense, Homeland Security) are especially troubling because those agencies are charged with keeping Americans safe.

Speaking of why his group is collecting vacancy data, he said “this is not about big or small government. This is about making government run more effectively, and everyone has that in their interest, no matter what your political persuasion.”

The inaction on appointments has prompted outcry from both sides of the aisle, with Democrats and Republicans asking for open positions to be filled more quickly. Post reporters Lisa Rein and Abby Phillip chronicled this example in a story last week:

Republicans have become so alarmed by the personnel shortfall that in the past week a coalition of conservatives complained to White House Chief of Staff Reince Priebus. “We remain very concerned over the lack of secondary and tertiary executive-level appointments,” they said in a letter signed by 25 prominent conservatives called the Coalitions for America, describing their concern that the leadership vacuum will create “mischief and malfeasance” by civil servants loyal to Obama.

There are a few reasons Trump is so behind in staffing his government.

For starters, in an April Fox News interview, Trump indicated that he may not want to fill all the open positions, in anticipation of restructuring or cutting them altogether. Paul Light, a professor of public service at NYU and expert on government bureaucracy, said vacancies might not be the worst thing from the administration’s point of view.

“It doesn’t hurt Trump to have agencies that cannot move. They can’t regulate. They can’t implement,” he said. “They’re completely decapitated.” Light said having temporary officials instead of permanent appointees could make it easier for the administration to eliminate positions.

Another factor at play is that the administration’s slow start allowed competing priorities to take precedence in the Senate. And yes, a more combative partisan opposition has played a role, with Democrats delivering Trump’s nominees more “no” votes than any other Cabinet within its first few months.

But Trump is nominating people with less government experience and complex financial backgrounds to untangle and has avoided anyone who voiced opposition to his candidacy during the campaign. These factors have led to difficulty finding candidates that can pass government ethics requirements that they separate themselves financially from what they’ll be overseeing. Several of Trump's nominees have had to withdraw from consideration before they got confirmed because they failed to demonstrate they would do this.

Cabinet secretaries have also butted heads with the White House over whom to hire.

Here’s a full rundown of how many positions have been acted upon at each of the 15 major Cabinet agencies, compared with previous administrations. The Post and the Partnership for Public Service are tracking the status of more than 550 key positions here.

Jump to a department: Agriculture  |  Commerce  |  Defense  |  Education  |  Energy  |  Health and Human Services  |  Homeland Security |  Housing and Urban Development  |  Interior   |  Justice |  Labor  |  State  |  Transportation  |  Treasury  |  Veterans Affairs

Note: Judiciary and non-civilian positions, failed nominations and holdovers from previous administrations are excluded.