You’ll be correct far more often than not if you simply assume that whatever a government tells you is a lie. It will also preserve your sanity. From Tho Bishop at mises.org:
Today the Washington Post published a bombshell report titled “The Afghanistan Papers,” highlighting the degree to which the American government lied to the public about the ongoing status of the war in Afghanistan. Within the thousands of pages, consisting of internal documents, interviews, and other never-before-released intel, is a vivid depiction of a Pentagon painfully aware of the need to keep from the public the true state of the conflict and the doubts, confusion, and desperation of decision-makers spanning almost 20 years of battle.
As the report states:
The interviews, through an extensive array of voices, bring into sharp relief the core failings of the war that war is inseparable from propaganda, lies, hatred, impoverishment, cultural degradation, and moral corruption. It is the most horrific outcome of the moral and political legitimacy people are taught to grant the state. persist to this day. They underscore how three presidents — George W. Bush, Barack Obama and Donald Trump — and their military commanders have been unable to deliver on their promises to prevail in Afghanistan.
With most speaking on the assumption that their remarks would not become public, U.S. officials acknowledged that their warfighting strategies were fatally flawed and that Washington wasted enormous sums of money trying to remake Afghanistan into a modern nation….
The documents also contradict a long chorus of public statements from U.S. presidents, military commanders and diplomats who assured Americans year after year that they were making progress in Afghanistan and the war was worth fighting.
