Donald Trump Jr. has emerged as the most influential Trump family member in the transition as the president-elect builds the most controversial Cabinet in modern U.S. history, according to a half dozen sources with knowledge of his role, elevating inexperienced loyalists over more qualified candidates for top positions in his administration.

Trump, who fiercely prizes loyalty, has long relied on family members for political advice, but which relative has his ear is known to vary.

This time, it is Don Jr., who has helped Cabinet contenders sink or rise to the fore — from championing Sen. JD Vance as his father's running mate to blocking former Secretary of State Mike Pompeo from joining the Cabinet, according to the sources, who include donors, personal friends and political allies.