WHEN Charles Grassley, chair of the Senate judiciary committee, said in the spring that he expected an imminent Supreme Court vacancy, all eyes turned to Anthony Kennedy. The 81-year-old native Californian, appointed by Ronald Reagan in 1988, is the court’s longest-serving member. He is also the median justice on a court often riven between four conservatives and four liberals on hot-button questions. At a reunion of his law clerks in June, Justice Kennedy widened everyone’s eyes when he said “there has been a lot of speculation about a certain announcement from me” before declaring with a wink that the bar was staying open late. The teasing may have fooled Mr Grassley for a time, but the Iowa senator is changing his tune. “Evidently”, he told Reuters last week, the Supreme Court vacancy is “not going to happen”.

Why is Justice Kennedy hanging around for another year? Maybe he would like to put in a full three decades before hanging up his robe. Maybe he isn’t anxious to give Donald Trump an opportunity to replace him. Or maybe the dazzling array of cases coming to the Supreme Court in the term beginning on October 2nd is just too tantalising to watch from the sidelines. Whatever his motivation, Justice Kennedy is likely to be the central player in a number of the most contentious disputes he and his eight colleagues will hear when they return from their summer break.

The first blockbuster comes on the second day of the term when the court hears Gill v Whitford, a challenge to partisan gerrymandering that Justice Ruth Bader Ginsburg says is “perhaps the most important” of the term and that Ian Samuel, co-host of First Mondays, a podcast about the Supreme Court, told listeners may be the “most important of your life”. The question is whether there are constitutional limits to gerrymandering, the practice of drawing district lines to maximise one party’s chances of electoral success. Following their sweeping wins in 2010, Republicans redrew electoral maps with stunning precision: 1.3m more voters opted for Democrats than Republicans in House races in 2012, but Republicans won a 234-201 majority. In Wisconsin, the focus of Gill, 51% of voters in 2012 picked Democrats for the state assembly, but Republicans wound up with 60 of the 99 seats. When the court last heard a gerrymandering challenge in 2004, Justice Kennedy couldn’t settle on a satisfactory limit but wrote that if “workable standards” were to surface distinguishing permissible from out-of-bounds partisanship, “courts should be prepared to order relief”. Gill isn’t being overhyped: a ruling against extreme gerrymanders could re-jig American politics at the state and national levels for the coming decade and beyond.

One week after the Gill hearing, on October 10th, Justice Kennedy will again be the focus of attention when the long-simmering dispute over Donald Trump’s executive order halting the refugee programme and freezing travel from several Muslim-majority nations gets a full hearing at the Supreme Court. The plaintiffs say that Mr Trump’s unprecedented ban on the entry of millions of foreign nationals has no basis in national security and is fuelled by unconstitutional prejudice toward Muslims. On that theory, several district courts, and two appeals courts, blocked the order. Now the Supreme Court will decide whether the travel ban originated in a defensible conception of presidential authority. Justice Kennedy appears to be the key vote in Trump v International Refugee Assistance Project for two reasons: he developed the doctrine of “animus” at the heart of rulings striking down laws that burden gays and lesbians, and his concurrence in a 2015 case suggested that immigration limits might be illegal if an official seems to be acting in “bad faith”.

Later in the term, the court will hear the ideologically fraught case of Jack Phillips, a baker who refused to make a cake for two men planning a wedding. Masterpiece Cakeshop v Colorado Civil Rights Divisionfeatures a clash of two ideals Justice Kennedy holds dear: gay rights and religious liberty. When he voted to make same-sex marriage a constitutional right in 2015, Justice Kennedy added a note to the ruling: “Those who adhere to religious doctrines may continue to advocate with utmost, sincere conviction that, by divine precepts, same-sex marriage should not be condoned”. The free-exercise clause of the first amendment, he added, “ensures that religious organisations and persons are given proper protection as they seek to teach the principles that are so fulfilling and so central to their lives and faiths”. Can Mr Phillips live out his life as a Christian man opposed to gay marriage if he must choose, as Colorado requires him to, between making cakes for all and making them for no one? Again, as his colleagues will in all likelihood be split four-to-four, that question may be Justice Kennedy’s to resolve.

There are other significant tussles coming up in October Term 2017 in which Justice Kennedy’s vote may be decisive, including a fourth-amendment mobile phone privacy case and petitions concerning labour-union fees and employment discrimination against gays and lesbians. But the busy year for the swing justice may be his last. He has reportedly told potential applicants for 2018 clerkships that he is considering retirement. Perhaps it’s best to take that with a grain of salt—as always, nothing is official until Justice Kennedy makes up his mind.