Nothing ends a Washington career like being branded an unacceptable national-security risk. That’s why officials adjudicating personnel-security cases must act in a mature, objective and nonpartisan fashion. But when it comes to vetting Trump appointees, they often aren’t. Instead, security clearances are being weaponized against the White House by hostile career bureaucrats, thwarting the president’s agenda by holding up or blocking appointees.

Consider the case of Adam Lovinger. Mr. Lovinger is a highly regarded and politically...