Secretary of State John Kerry was at the LBJ Presidential Library in Texas Wednesday night talking with filmmaker Ken Burns about Vietnam as part of the Vietnam War Summit. Kerry summed up the evening’s conversation by reminding Americans that “if we forget, we cease to learn.”

We absolutely should treat our returning veterans with dignity and honor, even those who “randomly shot at civilians, razed villages in fashion reminiscent of Genghis Khan, shot cattle and dogs for fun, poisoned food stocks, and generally ravaged the countryside.”

Kerry doesn’t seem to have forgotten much of the past and almost prefers to spend his time there when not jetting from one climate change summit to the next. We have to wonder how much he’s learned from it, though, especially following his relentless push to reach a deal with Iran on its nuclear program.

While Kerry was celebrating the agreement back home, Iranians were celebrating with familiar chants of  “Death to America” and “Death to Israel.”

While Kerry also ridiculed presidential candidate Mitt Romney for learning everything he knows about Russia from watching “Rocky IV,” the lesson he apparently learned from the Cold War was that Vladimir Putin’s aggression could be countered with a #UnitedForUkraine hashtag campaign.

Not only did Putin roll his tanks right over President Obama’s red line; Russian fighters have recently been buzzing U.S. destroyers in the Baltic Sea.

That wasn’t in “Rocky IV.”

State Department spokesman John Kirby recently elicited laughter from the press corps by insisting that the United States had never ruled out putting boots on the ground in Syria.

Maybe he forgot about this?

If we forget, we cease to learn.