CBS News has carried out a sweeping shake-up of "60 Minutes," firing correspondents Sharyn Alfonsi and Cecilia Vega and executive producer Tanya Simon as the network's editor-in-chief, Bari Weiss, remakes the most storied program in American broadcast journalism. Also let go were executive editor Draggan Mihailovich, after nearly three decades with the show, and producer Matthew Polevoy.

Into the executive producer's chair steps Nick Bilton, a documentary filmmaker and former New York Times columnist. Bilton becomes the fifth executive producer in the program's history and the first without a background in linear television, a choice that signals how thoroughly Weiss intends to reorient a broadcast institution that has run continuously since 1968.

The departures gut the correspondent roster. With Alfonsi and Vega out, and with Anderson Cooper having already announced his own exit, "60 Minutes" is losing three of its seven on-air correspondents in short order. For a program whose authority rests heavily on the continuity and reputation of its reporters, the turnover is destabilising.

The firings have not been clean breaks. Alfonsi, who joined the program in 2015, had clashed with Weiss over a segment on alleged abuses at CECOT, the El Salvador mega-prison; Alfonsi maintained the piece was delayed for political rather than editorial reasons. Vega, on her way out, said she had experienced efforts to insert political bias into stories and that reporting teams had begun holding back pitches on sensitive topics out of fear of internal repercussions.

Weiss, who built her profile as a commentator critical of what she cast as ideological conformity in mainstream newsrooms, arrived at CBS News with a mandate to shake up its culture. Her critics see the "60 Minutes" purge as the imposition of a particular editorial worldview on a program prized for its independence; her defenders frame it as overdue renewal. Either reading points to a fundamental contest over the direction of one of the last mass-audience news programs on American television.

The changes raise pointed questions about the future of the franchise. "60 Minutes" has weathered ownership changes, lawsuits and the long decline of broadcast audiences, but its identity has been remarkably stable. Replacing a third of its correspondents and installing an executive producer from outside television is the most consequential reinvention in a generation, and its success will be measured not in the boardroom but in whether the program's reporting retains the authority that made it a fixture.