McKINNEY, Tex. — The North Texas Job Corps Center squats behind a chain-link fence here in a suburb north of Dallas, accessible only through a gate manned 24 hours a day by guards hired to keep out intruders — and to keep in the center’s 436 students.

“It’s a little bit like prison,” said Donnell Strange, 17, who joined the electrical apprenticeship program about six months ago after struggling in school back home in Mansfield, near Dallas.

This is not what the founders of a flagship federal program with a $1.7 billion annual budget — an iconic Great Society program meant to prepare impoverished young people for the work force — had in mind. Started in 1964 by R. Sargent Shriver, President John F. Kennedy’s brother-in-law, as a ladder out of hopelessness, Job Corps today has become a 20th-century holdover incapable of meeting the demands of a national shortage of job-ready workers.

“Job Corps doesn’t work,” said Teresa Sanders, a former teacher at the North Texas center who quit in frustration in 2015 after a rash of violent episodes inside the center, but who keeps in touch with dozens of former students through a Facebook page. “The adults are making money, the politicians are getting photo ops. But we are all failing the students.”