Rupert Murdoch’s three adult children will retain control over their father’s media empire upon his death, a Nevada court has ruled after Murdoch launched a campaign to wrest away their power and give it all to his oldest son.

The New York Times reported on Murdoch’s loss, citing a sealed court decision that was filed on Saturday. The family battle took place outside of the public’s eye, despite attempts from the media to gain access to the trial.

Murdoch took three of his adult children, James, Elisabeth and Prudence, to court as he tried to completely remove their voting power over the trust Murdoch set up. The current trust structure gives all four adult children equal voting power over Murdoch’s empire, which includes Fox News and News Corp, but Murdoch wanted to give Lachlan, his oldest son and most likeminded child, complete control over the media companies. The change would have only impacted the voting power of the siblings, not their financial inheritance.

After reviewing the case, the Nevada commissioner Edmund Gorman concluded that Rupert and Lachlan Murdoch had acted in “bad faith” in their attempts to change the terms of an irrevocable trust that divides control of the company between Murdoch’s four oldest children.

In a statement, James, Elisabeth and Prudence told the Times: “We welcome Commissioner Gorman’s decision and hope that we can move beyond this litigation to focus on strengthening and rebuilding relationships among all family members.”

The 96-page opinion lambasts the media mogul, according to the Times, accusing him of organizing a “carefully crafted charade” to “permanently cement Lachlan Murdoch’s executive roles” inside the empire “regardless of the impacts such control would have over the companies or the beneficiaries” of the family trust.

Representatives for Murdoch did not immediately respond to a request for comment. Adam Streisand, one of Murdoch’s lawyers, told the Times that Murdoch planned to appeal the decision. Lawyers for James, Elisabeth and Prudence have not spoken publicly about the decision.

Now that the commissioner has issued his decision for the case, it will be up to a district judge in a probate court to ultimately accept the decision.

The ruling revealed Lachlan first pushed the case forward. Murdoch and his eldest son are said to have dubbed the attempt to change the trust “Project Harmony”, with the former believing it would see off the prospect of a power struggle within the family after his death. But his other children were reportedly blindsided by the move.

Murdoch worked with a team of high-profile lawyers for the case. Streisand has been involved in estate disputes of multiple celebrities, including Michael Jackson and Britney Spears. The former attorney general William Barr also helped Murdoch with his attempts to rewrite the trust.

If the decision holds, it is likely to have a major impact on the future of the rightwing media empire, which includes Fox News, the Wall Street Journal, the Times and the Sun in the UK and the Australian.

Murdoch, 93, is more politically aligned with Lachlan, his heir apparent. James, Elisabeth and Prudence are regarded as less conservative and James, in particular, has publicly criticized climate denialism in the media and accused US media of “propagating lies” that unleashed “insidious and uncontrollable forces” after the January 6 insurrection. James resigned from his role as a senior executive at News Corp in 2020. That same year, he and his wife donated $600,000 to Joe Biden’s presidential campaign.

Meanwhile, Lachlan, who took over as chair of News Corp in 2023, has privately voiced political opinions similar to his father and has attached himself to the growth in ratings and sales the media empire has seen since Trump’s rise in 2015, according to multiple reports.

Fox’s revenue for fiscal year 2024, which ended over the summer, was nearly $14bn. It is the most-watched cable news show in the US and received a bump in viewers and influence after Donald Trump’s first election in 2016.

Robert Thompson, a media scholar based at Syracuse University, said even after the court loss, the Murdochs may stick with their empire’s right wing-pleasing business model.

“The Fox model has worked very well,” said Thompson. Even if all the siblings have shared control, they will still all have to think about the companies’ bottom line.

“This is such a successful business model that anything that would jeopardize the steady course would be bad for everybody,” Thompson added. “I’m not completely convinced that these Murdochs are going to, in the end, be able to really revolutionize the behemoth that Dad created.”