Efforts to attract high-achieving college students to serve in U.S. government national security jobs often fail because the hiring process does not favor new blood, according to a new report from the nonprofit Center for a New American Security.

The hiring process can take more than two years—a long stretch for someone who has just completed a degree and is looking for their first full-time job.

There is interest in national security careers. A “sense of purpose or mission was the number one factor they considered when offered a job,” CNAS found in a survey. Government jobs were attractive even though compensation might be higher in the private sector.

Asked what they would do if simultaneously offered a federal government job or a similar private sector job that had twice the salary, respondents were evenly divided, with 50% opting for the bigger salary and 50% wanting the lower-paying mission-focused job.

What discourages national security employment is the entry process. Internships, a way in for new hires, are mostly unpaid, which is discouraging to someone with college debt. The federal hiring process includes a preference for veterans, and the competitive process also favors those with significant work experience, which a recent college graduate may lack. Internships are also difficult for recent graduates to get because of the time it takes to get a security clearance.

“In at least one case, a student was offered and accepted a summer internship during their fall semester, secured D.C. housing for the following summer, but was unable to start the internship because of delays in the clearance process—thus leaving them in the position of paying for a costly lease without being able to participate in the internship program,” says the CNAS report, titled “The Future of Civilians in National Security.”

The report recommends that Congress and the executive branch make the hiring process easier to navigate, with a goal of hiring and onboarding new employees in 21 days or less.

Those interested in national security positions also need to be better prepared. “Students should study the reporting required for the clearance process before they pursue international professional or educational opportunities,” the report finds. It also says those interested in government service “should be mindful of salary differences between private and federal employment.”

The full survey and report are available here.