Shapira was the most vocal of the ministers opposing a preemptive Israeli attack before the Six Day War. "How dare you go to war when all the circumstances are against us", he said to the IDF's chief of staff, Yitzhak Rabin. The other National Religious Party ministers joined Shapira in this stance. During the war, he opposed opening a new front in the Golan Heights. Despite his moderate worldview, he acted to include the right wing parties in the government on the eve of the war. This effort resulted in the establishment of a national unity government.