Right now, more than 500,000 federal employees and government contractors are awaiting security clearances.

That poses a serious threat. The enormous backlog of clearance applications prevents talented analysts, engineers, and coders from working on today’s most critical national security challenges. Some applicants wait more than 350 days before starting their jobs. Unsurprisingly, many highly qualified and badly needed security officials take other employment due to the unreasonable delay.

The high-stakes waiting game leaves our nation needlessly short-handed and wastes taxpayer money. To keep America safe, the Trump administration should make ending the clearance backlog an urgent priority.

There are two main reasons for the current clearance build-up.

The first is the data breach that compromised the Office of Personnel Management in June of 2015. That hack forced the agency to shut down its systems for about a month to improve safeguards, bringing all background investigations to a halt.

A few months later, the Defense Security Service, the agency that reviews clearance requests before passing them along to OPM, suffered budget cuts. As a result, DSS temporarily stopped processing almost all requests for government contractors.

In both cases, pending applications piled up quickly. In four weeks, DSS alone faced a backlog of 10,000 clearance applications. OPM is now working through roughly 500,000 requests.

The bureaucratic review process was already too slow — and these two incidents only made things worse. While investigations for mid-level clearances were supposed to take only 74 days last year, the average wait was about double that. “Top Secret” clearances took over 200 days to process during the first quarter of 2016 and close to 400 days to clear during the first quarter of 2017.

With threats mounting each day, America can’t let qualified defense professionals sit idle.

Consider cyber-warfare, which nearly three in four Americans see as a critical threat. It’s easy to see why; hackers attempted to infiltrate both the Republican National Committee and Democratic National Committee last year, demonstrating how a cyber-attack could disrupt our institutions.

The current clearance system also wastes taxpayer money. Newly recruited defense professionals still get paid by their employers while their background checks are cleared.

One step to reduce the backlog? Eliminate application redundancy. Some agencies immediately grant applicants a certain clearance level if they’ve met requirements at a different agency. To minimize wasteful reapplications, federal regulators should make this policy — called reciprocity — mandatory across all agencies.

The Trump administration could also ask Congress for funding to help agencies bolster staff for clearance applications. The National Background Investigations Bureau, for example, took on 400 new investigators in 2016 and aims to enlist 200 more in 2017.

The clearance build-up is already hindering vital projects, squandering resources, and discouraging talented Americans from pursuing national security jobs. By enacting immediate, practical reforms, President Trump and his team can eliminate this backlog — and make sure our nation remains safe.

Michael James Barton, a policy fellow at ARTIS International, served as deputy director of the Middle East Policy Office in the Office of the Secretary of Defense from 2006 to 2009. Earlier, he served on the Homeland Security Council at the White House. This piece originally ran in The Hill.