For much of modern television history, David Letterman was defined by irony and distance. For more than three decades, his humor shaped late-night television, puncturing celebrity and political pretension with a shrug and a joke. Since his retirement from network television in 2015, however, Mr. Letterman has increasingly traded irony for urgency — and in recent remarks, he delivered one of his bleakest assessments yet of American media and politics.

Mr. Letterman returned to the public eye shortly after stepping down from The Late Show with a Netflix interview series, My Next Guest Needs No Introduction, which positioned him less as a satirist than as a reflective interlocutor. His first guest was Barack Obama, and the conversation set the tone for the series: long-form, sober and focused on structural issues like inequality, globalization and political polarization.

But Mr. Letterman’s sharpest recent commentary has been reserved for the state of American media, particularly broadcast networks he once helped define. Speaking publicly after what he characterized as punitive actions against late-night hosts critical of Donald Trump, Mr. Letterman accused television executives of yielding to political pressure rather than defending editorial independence.

He cited the treatment of Stephen Colbert and Jimmy Kimmel, both of whom have been frequent and pointed critics of Mr. Trump. Mr. Letterman described what he viewed as network decisions motivated by fear — not of audiences, but of power.

“They took care of Colbert,” Mr. Letterman said in comments included in the video, calling the move “inexcusable” and suggesting that corporate owners were attempting to avoid antagonizing the White House. Of Mr. Kimmel, he said he felt “bad,” adding that the direction of media consolidation and risk aversion was becoming unmistakable.

His harshest words were reserved for CBS News, an institution Mr. Letterman described as having abandoned its historical mission. He invoked the legacy of Edward R. Murrow, recalling the network’s role during World War II and its reputation for independence and courage. That tradition, Mr. Letterman argued, had been “eviscerated” by modern corporate leadership.

The critique was not limited to nostalgia. Mr. Letterman framed the current media environment as one in which fear of political retaliation — regulatory, financial or rhetorical — has narrowed the boundaries of acceptable criticism. In his telling, the result is a form of “managed media,” shaped less by journalistic judgment than by calculations about access and safety.

What made his remarks notable was not simply their severity but their source. With more than 6,000 network episodes to his name, Mr. Letterman is not a marginal figure railing against a system from which he was excluded. He is a central architect of that system, now warning that it no longer functions as intended.

Mr. Letterman also rejected the idea that electoral cycles alone can resolve what he sees as a deeper erosion of democratic norms. He expressed frustration with arguments urging patience until the next election, suggesting that such thinking underestimates both the speed and the scale of institutional change. In his view, waiting risks normalizing conditions that should instead provoke immediate scrutiny and resistance.

The video’s narrator extended Mr. Letterman’s argument further, asserting that political volatility and enforcement actions by federal authorities have already produced deadly consequences. Those claims were presented as opinion and advocacy rather than independently verified reporting, but they underscored the emotional register in which Mr. Letterman’s comments have been received by some audiences.

Notably, Mr. Letterman did not call for specific political actions, nor did he align himself with a party or movement. His warning was broader and, in some ways, more traditional: that a free society depends on institutions willing to absorb pressure rather than reflect it.

In a media landscape increasingly fragmented by algorithms and ownership consolidation, Mr. Letterman’s intervention stands out for its clarity. It is the voice of someone who benefited from strong institutions now questioning whether they remain strong enough to protect themselves — or the public — from power left unchecked.

For a figure once known for detachment, the message was unmistakably personal. The joke, as Mr. Letterman seems to suggest, is no longer enough.