The Vietnam War has been over, officially, for four decades. In that span of time, according to filmmaker Peter Davis, America both learned—and forgot—the lessons from that war.

Davis won an Academy Award in 1975 for his documentary on the war, "Hearts and Minds." He joined Jim Braude and Margery Eagan to revisit the film and examine how the legacy of Vietnam has reverberated into American foreign policy today. 

On the lessons from the Vietnam War:

DAVIS: I think we learned a lot at first, which is: don't play in away games. Don't go to war against countries that haven't attacked us, that haven't done anything that even threatens us. That really stayed learned for a generation, but 9/11 was like a blow to the head causing amnesia, and we forgot the lessons of Vietnam.

On leadership and war:

DAVIS: I don't think that power is every going to watch itself. We have to watch power. President Obama came to office, to the presidency with the idea that he would be candid, he would tell us things. After all, he opposed the War in Iraq. But once in the presidency he saw these two wars as necessities, rather than terrible wrong turns. I've always thought Osama bin Laden must have died happy, because he sucked us into two wars against Muslim countries.

"...9/11 was like a blow to the head causing amnesia, and we forgot the lessons of Vietnam."

On America's open-ended mission in the War on Terror:

DAVIS: [Officials] begin to get CIA briefings every day, and of course Pentagon pressure every month, to keep it going, keep the war machine going. Otherwise, Pakistan may fall into chaos, so we have to stay in Afghanistan. Iraq may fall to ISIS, so we have to stay in Iraq. I think that what they forget is context. Why do we want to make the Middle East into a quicksand that draws us in and never lets us out?

On media coverage of the wars, then and now:

DAVIS: It helps us stay there. Of course it helps us stay there. There have been very good films made about those two wars, but in terms of nightly news coverage, it's true—there isn't that much. There isn't that much interest. No one has to go to war. No one gets deployed to Iraq and Afghanistan who hasn't volunteered...Since we don't have a draft anymore, we don't have people whose mothers and fathers and lovers say, 'I demand they not go.'

To hear more from filmmaker Peter Davis, tune in to his full interview on Boston Public Radio above.

This interview has been edited and condensed for clarity.