I'll try to play for the side of anti - flag burners and make an argument that flag burning is immoral.
1) A flag represents a nation.
2) A nation is more then "a patch of dirt". The land a nation inhabits in only one component of the nation. Its government, its people, and its culture are also components of the nation.
3) Therefore, burning a flag is a statement against not only the government, but also the people and the culture of the nation. Basically, it's an aggressive act against the ethnicity which flag is being burned.
Thoughts?
The immediate assumption of nationalism, which I regard to be a very dangerous beast indeed, turned me off what is otherwise a fairly sound argument.