As President Donald Trump looks to reshape the executive branch, he's avoiding the words "you're hired."

Trump's choice of Kevin McAleenan as acting replacement for Homeland Security secretary Kirstjen Nielsen spotlights the president's increasing reliance on a once-obscure federal statute that governs how to fill vacant federal posts. It also raises fresh questions about his reliance on temporary appointments for key security roles.

The reality-star president, who once made staff churn into prime-time television, has overseen massive turnover in just two years in office. But he's shown little concern over creating uncertainty about the leadership of some of the country's most important agencies.