Ketanji and Elena's partner on the liberal wing of the Supreme Court Crossword Clue

 The answer to the crossword clue "Ketanji and Elena's partner on the liberal wing of the Supreme Court" is Sonia.

Sonia Sotomayor is the third and current Hispanic justice on the Supreme Court of the United States. She was nominated by President Barack Obama and confirmed by the Senate in 2009. Sotomayor is considered to be a liberal justice and is often joined by Ketanji Brown Jackson and Elena Kagan in their votes.

The clue is a bit of a pun. The word "partner" can mean a spouse or a colleague. In this case, it is referring to Sotomayor as a colleague of Ketanji Brown Jackson and Elena Kagan.

I hope this helps!