For almost a decade, the annual commemoration of the terrorist attacks of Sept. 11, 2001, has been seen as a day of national unity and sober remembrance. This year, contentious issues of religious freedom and national identity threaten to color the ninth anniversary of those tragic events.

Controversies over calls to burn the Koran and an ongoing debate over a proposed mosque and Islamic cultural center near Ground Zero in New York are drawing particular attention as the anniversary nears, sparking questions about how 9/11 became so politicized.

The reality is that, with rare exceptions, the meaning of those attacks has rarely been free of political overtones or debate. Common ground in the months after the attacks quickly gave way to partisan division over combating terrorism. What may be different this year is that earlier debates about who was "strong" in the fight against terrorism and who was not have been supplanted by questions about Islam and religious freedom....