WASHINGTON  Chief Justice John G. Roberts Jr. called on President Obama and the Senate on Friday to solve what he called “the persistent problem of judicial vacancies.”

The plea, in the chief justice’s annual year-end report on the federal judiciary, was an echo of one from his predecessor, Chief Justice William H. Rehnquist, who made front-page news on New Year’s Day in 1998 by criticizing the Senate for failing to move more quickly on President Bill Clinton’s judicial nominees.

Both chief justices were appointed by Republican presidents, and both said that their interest was not in particular appointees but in a judiciary functioning at something like full strength.

“We do not comment on the merits of individual nominees,” Chief Justice Roberts wrote on Friday. “That is as it should be. The judiciary must respect the constitutional prerogatives of the president and Congress in the same way that the judiciary expects respect for its constitutional role.”