In most democracies, the highest court in the land is too obscure to merit an end-of-term review. The US is not most democracies. Its Supreme Court justices, who have risen for the summer, are more scrutinised than all but a few politicians. Their confirmations to the bench are more divisive than most elections. When they formed a 6-3 conservative majority last October, after the death of the liberal Ruth Bader Ginsburg, an age of judicial Republicanism seemed to beckon.

That shift is real enough, even if it is patchier than the left feared and the right hoped. The past month alone is illustrative. In June, the court upheld Barack Obama’s Affordable Care Act, ruling that the plaintiffs (including the state of Texas) lacked the standing to bring the case. Almost concurrently, the court weakened the 1965 Voting Rights Act for the second time in a decade. As a result, states could have more room to craft voting rules that lead to racial disparities.

The ambiguity does not end there. Less often than expected over the nine-month term have the conservatives acted as a monolith. Chief Justice John Roberts and each of Donald Trump’s three appointees have joined the liberals at various points. True, in a recent case about adoption by gay parents, the court sided on narrow grounds with a Catholic agency against the city of Philadelphia. But it did so unanimously.

Owing to both the substance of these rulings and their frequently cross-partisan nature, Democrats and Republicans enter the summer grumbling but not seething about the court. Such an outcome would have been considered a victory for political peace last October. The suspicion remains that, more than “liberal” or “conservative”, the bias of the Roberts court is towards its own survival. The chief justice has a concern for the perceived legitimacy of his institution that a crude rightward turn would threaten.

The question is how long this uneasy calm will last. There are three reasons to worry. One is the gathering trend. As quiet as the term mostly was, it ended on a conservative note: as well as the Voting Rights Act ruling, the court limited disclosure requirements for charitable donors. This may be a case of the conservative majority taking time to finds its voice. Second, some of the most sensitive issues are yet to even come before the justices. Cases to do with abortion and gun rights await them when they reconvene in October.

There is one more cause for concern and it involves President Joe Biden’s expansive vision of government. As bound up as it is with cultural questions, the Supreme Court spends much of its time construing the right of the federal government to infringe on business. The ideological tests imposed by the Heritage Foundation and other conservative judge-vetters include hostility to the Environmental Protection Agency, for example, not just to incursions on religious practice.

This matters all the more under a president who envisages a more active state than even his Democratic predecessors did. The more that Biden regulates on behalf of the environment, labour standards and racial and gender equity, the more likely a heavily conservative court is to assert itself. Seemingly technical cases can have huge real-world effect without incurring the political hubbub of the culture wars.

Conservatives have raised their hopes of judicial ascendancy before, only to denounce their appointees as sell-outs. Roberts himself is barracked as such. This time, they have votes to spare and, in Barrett, a perceived stalwart for the cause. However slow and fitful, the omens of a dominance to come are ever harder to miss.