Cultural divisions in Northern Ireland are similar to the US

For more than 50 years the court has fluctuated between conservative and liberal philosophies, and how they interpret the US constitution. The nine-member court is the final arbiter of that document, and played a pioneering role in the civil rights era of the 1950s and 60s. It forced bitterly reluctant states to end segregation.

Most of the leading roles played by the court have been in pushing agendas that would typically be deemed to be on the left, or in American parlance liberal, end of the spectrum. The 1973 Supreme Court ruling Roe versus Wade enshrined the right of women to have an abortion early in pregnancy.

A key part of any president’s legacy is his appointments to the court, which can have lasting consequences. A number of Republican presidents have pushed back against the progressive rulings of the court, notably Ronald Reagan. One of his appointments was Antonin Scalia, who was elevated to the court in 1986 and who has died at 79. There will now be a political battle in Congress over President Obama’s replacement for Mr Scalia, given that the court leant conservative, 5 to 4. Mr Scalia, a Roman Catholic, was traditional on social issues.

In Northern Ireland there is growing political confusion on such topics. Unionist MLAs are overwhelmingly conservative on matters such as abortion, and nationalist MLAs overwhelmingly liberal on matters such as gay marriage. A more logical divide would be for conservative Protestants and Catholics to align on key cultural questions, as in America, and progressive Protestants and Catholics (and neithers) to align against them. There is also no reason why a Catholic should be on the left economically and a Protestant on the right, but nationalist and unionist traditions tend to divide that way.

If Northern Ireland ever moves from such divisions, it will be a sign that constitutional matters are no longer dominant.