According to history and Tricky D!ck, in the Vietnam War, in 1968 new year, the North Vietnamese and Vietcong launched the Tet Offensive.

Richard Nixon, later said that the minute he was told about the Tet Offensive, at that very moment he realized the war was unwinnable.

However, even this is what Nixon thought, and Nixon became President later that year, the war still dragged on. A few years later were they finally able to sign a ceasefire. Was it Kissinger and Uncle Doc at the Paris negotiating table, got to look that one up. Two years after that, North Vietnam overruns the south leading the evacuation of the American embassy in Saigon.

So Nixon was right, but it took a few years to show he was completely right, which kind of means anything could have happened to change the course of history.

This Bernie guy seems like he is having the same Nixon epiphany over the Tet Offensive, but Bernie realizes the situation of the Middle East, Ukraine/Russia, China, may marginalize the USA all at once down the road.

Something can happen to change the course of history.