President Obama put his foot in his mouth by referring to a “Polish death camp” as he was awarding a posthumous Presidential Medal of Freedom to Jan Karski, a Polish hero who tried to stop the Holocaust. There couldn’t have been a worse time to make this blunder of calling German concentration camps “Polish.”

The only things Polish about Nazi concentration camps like Auschwitz were the victims. Auschwitz is a German name; German guards patrolled it; the German words “Arbeit macht frei” hang over the entrance.

Poland has been one of America’s greatest allies in the War on Terror, and Obama’s comments are putting a strain on this important relationship. Our president’s comments are such a scandal over there that Poland’s president, prime minister and foreign minister have all demanded that he apologize.

Karski was a hero for Poles. And he was such a hero for Jews that Israel made him a citizen after the war. He risked his life to sneak into the Jewish ghetto, where he promised Jewish leaders he would tell their story to the Allies. He also disguised himself as a Ukrainian guard to visit a German concentration camp.

Then Karski traveled across war-torn Europe to London and Washington to deliver his eyewitness account of Nazi Germany’s mass murder of Jews.

President Franklin Roosevelt ignored Karski’s pleas to help the Jews. Obama was supposed to set the record straight — but made things worse by using a phrase that insinuates that Poles were responsible for the camps.

This is not just semantics. The documentary “Upside Down” showed that Canadian and American schoolchildren thought Poland built the concentration camps because they’re often referred to as “Polish.”

After the Kosciuszko Foundation began a drive two years ago asking news outlets to stop using the phrase “Polish concentration camps” to refer to the German horrors in Nazi-occupied Poland. The Wall Street Journal, The New York Times, the Associated Press and other media organizations changed their stylebooks.

Yet the White House has issued only a lukewarm statement from a press officer saying that Obama “misspoke.”

Misspoke? This offensive phrase was on the teleprompter. That means the president’s staff didn’t care enough about this issue to research Karski’s history on the Internet.

Had they done so, they would’ve learned that Karski was not the only Pole who tried to save Jews from the German death camps. The underground created a clandestine organization called Zegota — the Polish Council to Aid Jews, which rescued tens of thousands of Jews during the Holocaust. They’d have learned about Irena Sendler, who rescued 2,500 Jewish children from the Warsaw ghetto and found Poles willing to hide them.

Yes, there were cases of Poles killing Jews during the war — but no country did more to save Jews during the Holocaust than Poland. There are 6,339 people from Poland honored at Yad Vashem in Israel as righteous folk who saved Jews during World War II — more Poles than nationals of any other country.

Poles thought that by honoring Karski, Obama was going to set the record straight about the death camps. But by using this phrase to honor a Polish war hero, our president poured salt on wounds that keep getting scratched nearly seven decades after the war ended.

Alex Storozynski is president and executive director Ӭ of The Kosciuszko Foundation and a Pulitzer Prize-winning journalist. (Copyright 2012 NYP Holdings, Inc. 05/31/12)