Unlike in Ireland, where a simple majority of votes in a referendum is enough to change Bunreacht na hÉireann, the United States constitution is extremely difficult to amend. At a time such as this, with the US bitterly split along partisan lines, the document is virtually unamendable. That gives the US supreme court – the final arbiter of the constitution – immense (and far too much) power, and makes any change in its personnel one of the most significant moments in national life.
Few retirements are potentially as momentous, however, as that of Anthony Kennedy, the 81-year-old Reagan-era appointee who has announced he is stepping down after three decades on the court. Since the retirement of Sandra Day O'Connor in 2006, Kennedy has been the decisive "swing" vote on the nine-judge court. He often sides with conservatives, and in the process has played a significant part in the erosion of American democracy in recent years. He wrote the majority judgment in Citizens United, which opened the door to unlimited election spending by corporations. He upheld gun rights and supported the unravelling of the Voting Rights Act, which has allowed states to make it harder for some Americans, including minorities, to vote.
On social issues, however, he has helped shore up liberal precedent. He defended the seminal abortion judgment, Roe v Wade, from right-wing attack and led the way in granting same-sex couples the right to marry. In an institution that spends too much time looking at itself in the mirror, Kennedy was an outward-looking judge who travelled widely and drew on foreign influences.
Kennedy's retirement was not unexpected, but its effects will be seismic nonetheless. It gives Donald Trump perhaps the most consequential decisions of his presidency, because while many policies can be changed by a president's successors, supreme court judges serve for life. That means Trump's nominee, widely expected to come from the hard-right, will lock the court into a conservative majority for at least a generation. That will imperil landmark judgments on questions where Kennedy tipped the scale towards the liberals. Roe v Wade has never been in greater jeopardy.
Democrats will find it harder than ever to block an ideologically extreme nominee. Thanks to the disgraceful behaviour of its leaders, the Republican Party last year dismantled the filibuster – a vital tool that had underpinned the legitimacy of the court for decades – en route to confirming Trump's last nominee, Neil Gorsuch.
American democracy is in a precarious state. The Republican Party has been hijacked by extremists, and the White House is controlled by a man with authoritarian instincts and contempt for democratic norms. Liberals may soon no longer be able to count on the courts to hold those forces in check. The ballot box is their only hope.