BREAKING: Supreme Court Justice Anthony Kennedy announces his retirement

Supreme Court Justice Anthony Kennedy announced on Wednesday in a letter to President Donald Trump that he will be retiring on July 31.

Kennedy's replacement will be a particularly important nomination for the president, since Kennedy is generally considered to be the swing vote on the Supreme Court.

Who is Supreme Court Justice Anthony Kennedy?

Kennedy, a Ronald Reagan nominee, is the 14th longest-serving justice of all time. Before that he was appointed by Gerald Ford to the 9th Circuit Court of Appeals. Coincidentally, one of his last actions as justice was to side with the court's four conservative members to overturn a decision by the 9th Circuit Court, which had decided that Trump's controversial travel ban was illegal.

Although he also frequently voted with the liberal justices in the past, Kennedy helped give conservatives 5-4 wins on several Supreme Court cases this week. In addition to the travel ban case (Trump v. Hawaii), Kennedy provided the slim margin needed for the Supreme Court to rule that a lower court needed to rehear the case of a florist who refused to create arrangements for a gay wedding (Arlene's Flowers Inc. v. Washington), and to rule that public sector unions could not force employees to pay dues (Janus v. AFSCME).

What did the resignation letter say?

Kennedy's letter was short and to the point. Addressed to "My dear Mr. President," it read:

This letter is a respectful a formal notification of my decision, effective July 31 of this year, to end my regular active status as an Associate Justice of the Supreme Court, while continuing to serve in a senior status, as provided in 28 U.S.C § 371(b).

For a member of the legal profession it is the highest of honors to serve on this Court. Please permit me by this letter to express my profound gratitude for having had the privelege to seek in each case how best to know, interpret, and defend the Constitution and the laws that must always conform to its mandates and promises.

Respectfully and sincerely,

Anthony M. Kennedy

Who will replace Kennedy?

Since Kennedy's retirement was only just announced, Trump has not officially announced who Kennedy's replacement might be yet. However, the president has said in the past that he would select a new justice from a list of 25 names compiled with help from the Heritage Foundation and the Federalist Society.

This list includes people like Sen. Mike Lee (R-Utah), Texas Supreme Court Justice Don Willett, and Diane Sykes, a judge for the 7th Circuit Court of Appeals and the former wife of conservative political commentator and frequent Trump-critic Charlie Sykes. With the exception of Sen. Mike Lee, all the nominees on the list either are or were lower court judges.

This is a developing story and will be updated