Ruth Bader Ginsburg intimated on Friday that the US supreme court will soon issue more 5-4 decisions in watershed cases. The justice also said she regarded the retirement last year of swing vote Anthony Kennedy as “the event of greatest consequence for the current term, and perhaps for many terms ahead”.

Ginsburg, 86, told a legal conference in New York the highest court had “heard argument in 70 cases” plus “five summary per curiam decisions – opinions rendered without full briefing or oral argument”.

“That brings to a total of 75 decisions already rendered plus those remaining to be released before the court recesses,” Ginsburg said. “As of today, we have announced 43 decisions in argued cases. That leaves a large number – 27 – to be announced in the remaining June days.”

Only 11 of the 43 announced argued cases were determined by 5-4 or 5-3 votes, Ginsburg said.

“Given the number of most-watched cases still unannounced,” Ginsburg said, “I cannot predict that the relatively low sharp divisions ratio will hold.”

Ginsburg’s remarks appeared to presage dramatic splits on two big issues: the placing on the US census of a question about citizenship and the politicization of voting districts.

The census case stems from the commerce secretary Wilbur Ross’ plan to ask respondents to the 2020 survey if they are US citizens.

The proposed question – “Is this person a citizen of the United States?” – provides five possible answers: whether respondents were born in the US, a US territory, abroad to US citizen parents, became naturalized US citizens or are not citizens.

A number of states sought to block the question. Opponents say many immigrants will not complete census forms featuring it, due to fears that their immigration status may be used against them.

Because census results are used to determine how seats in Congress are apportioned, opponents of the question say an artificially deflated count would deal a blow to states with many immigrants, such as California and New York, which overwhelmingly vote Democratic.

Census numbers also decide how much federal money cities and states receive. States opposing the immigration question contend that it is unconstitutional. But the court’s conservative majority appears poised to uphold the plan.

The case on political districts deals with whether state legislatures can forge congressional delegations that starkly contrast with the distribution of voters, as well as alleged race-based gerrymandering.

In 2016, North Carolina Republicans took 53% of the vote and landed 10 of 13 congressional seats. In 2018, Democrats won a slight majority but took just three congressional districts. Republicans who led the state legislature came up with apparently advantageous voting maps.

In Maryland, meanwhile, Democrats established voting districts that would benefit their party. At issue is whether such practices violate voters’ rights.

“However one comes out on the legal issues, partisan gerrymandering unsettles the fundamental premise that people elect their representatives, not vice-versa,” Ginsburg said in New York.

Her remarks came amid a dramatic ideological shift on the court. The retirement last summer of Kennedy set the stage for the ascent of Brett Kavanaugh, a stringent conservative, in a confirmation process hit by allegations of sexual misconduct.

Kavanaugh’s confirmation came 18 months after Donald Trump’s first pick, Neil Gorsuch, was sworn in as the 113th justice, arguably tilting the panel right for decades to come. Gorsuch filled a seat vacated by the death of Antonin Scalia during Barack Obama’s second term in office. That seat was held open by the Senate majority leader, Mitch McConnell, who refused to grant a confirmation hearing to Obama’s nominee, Merrick Garland.

To indignant protest from Democrats and progressives, McConnell recently said he would fill any vacancy created in Trump’s last year of office.

Ginsburg said Kennedy’s retirement “was, I would say, the event of greatest consequence for the current term, and perhaps for many terms ahead”.

But she also complimented Kavanaugh’s hiring practices, saying the controversial justice “made history by bringing onboard an all-female law clerk crew”.

“Thanks to his selections,” Ginsburg said, “the court has this term, for the first time ever, more women than men serving as law clerks.”

Ginsburg was the second woman ever appointed to the court and has become a feminist and pop cultural icon. She also highlighted the gender gap in lawyers she sees before the bench.

Just 21% of lawyers who presented oral arguments this term were female, she said, adding: “Women did not fare nearly as well as advocates.”

• This article was amended on 10 June 2019 to clarify quotes attributed to Ruth Bader Ginsberg about the supreme court’s unannounced decisions.