Why Arar was under suspicion

Arar case began amid fear of attack on Ottawa

Canadian counterterrorism agents were investigating the possibility of an al-Qaeda plot to blow up targets in Ottawa when they began a probe that would lead to the detentions of Maher Arar and several other Canadian Muslims half a world away.
...
In late August, 2001, U.S. border guards discovered a single sheet of paper — a schematic map of Ottawa marking government buildings and nuclear research facilities — in an 18-wheeler driven by a man named Ahmad Abou El-Maati.

The story goes on to describe the chain of events that ultimately led to Arar's deportation to Syria. It also quotes a "government source" saying:

I know a lot of people don't believe this, but we are involved in a war — it's called a war on terror. And in any kind of war, innocents are hurt.

No, we're not at war. The danger from terrorism is real but when you allow the Bush administration to frame it as a "war", you allow it to justify the erosion of civil liberties and the abuse of the justice system in a way that would never be tolerated if you view terrorism as a criminal justice issue. It's become increasingly apparent that the Bush administration used 9/11 in a cynical manner to push a prior agenda. Whether Canadian officials were just as cynical, or simply overreacted, remains to be seen but the Arar case makes it plain that something's wrong.

...Muslim and Arab groups are beginning to push for a broadening of any public inquiry into the Arar case to examine why information gathered in Canada seems to be playing a recurring role in the detention of Canadians abroad.

They have my support.