The White House said Friday that President Obama had written a letter to the Polish president expressing “regret” for using the term “Polish death camp” this week while honoring a Polish World War II resistance hero rather than wording that would have made it clear that he meant a death camp operated by Nazi Germany on Polish soil. Poles had no role in running the camps, and many were killed in them. “In referring to ‘a Polish death camp’ rather than ‘a Nazi death camp in German-occupied Poland.'”