Supreme Court Justice Anthony Kennedy is set to retire, giving President Donald Trump the chance to cement a conservative majority on the top court.
The conservative has been a pivotal vote on many decisions including the 5-4 rulings that decided same-sex marriage and upheld abortion rights.
In his letter to Mr Trump, Justice Kennedy expressed “profound gratitude” for having served in the highest court.
Justice Kennedy, 81, will retire on 31 July, he said in his letter.
He is the second oldest justice on the nine-member court.
He said his retirement was motivated by his decision to spend more time with his family.
“It has been the greatest honour and privilege to serve our nation in the federal judiciary for 43 years, 30 of those years on the Supreme Court,” Justice Kennedy wrote.
