sitting #2
sittingのこうした用法は2度目?3度目?
"currently holding an office"(Webster)、つまりは「(議員などが)現職の」を表す形容詞的用法でしたね(cf. sitting members)。(UG)
At her confirmation hearing last month, Mrs. Kennedy noted that her father had hoped to be the first sitting president to make a state visit to Japan.
“If confirmed as ambassador, I would be humbled to carry forward his legacy in a small way and represent the powerful bonds that unite our two democratic societies,” she said.
http://blogs.wsj.com/japanrealtime/2013/10/17/senate-confirms-caroline-kennedy-as-u-s-ambassador/