Rabbi Levi Yitzchak Horowitz (1921-2009), better known as the Bostoner Rebbe, was one of the 400 rabbis who took part in the 1943 march to the White House to urge the rescue of European Jews.

At the time of the march, Horowitz was a recently-married rabbinical student at the Mesivta Torah Vodaas yeshiva, in Brooklyn. In a postwar interview, he reflected on President Franklin D. Roosevelt’s refusal to meet with the the protest leaders: “Today, for ordinary citizens to meet with the president is not as extraordinary as it was in those days. Still, given the situation, we thought President Roosevelt would meet with us, even if just for a few minutes. I was very surprised and disappointed that he was not willing to meet with us. Years later, when we began to realize the extent of the Holocaust, I felt even more disappointed at the president’s response–or I should say lack of response–to us.”
He added: “We had no idea what the march might accomplish, and we certainly did not yet appreciate the full extent of what was happening in Europe, but we simply felt it was very important that we protest.”

Rabbi Horowitz said it was his participation in the 1943 march that inspired him to organize busloads of Boston Jews to travel to Washington, D.C., during the 1967 Arab-Israeli war, to urge U.S. support for Israel. “Thinking back now, I am sure that my experience in 1943 played a major role in the way I reacted in 1967,” he said. “That was the lesson I took from 1943.”

Sources: Medoff, The Day the Rebbe Marched, p.A4.