History has shown that when a nation attacks its citizens something happens to its relationship with its people. The side that supports the attack feels empowered and justified. The side that is attacked ceases to feel loyalty to the state. Thus the state, by its actions, has abandoned a portion of its population and begins a program of repression of its own. This is the reality of Iran in June of 2009. In other places and at other times in history here is what happened next.
In 1776 the English King's troops fired on his subjects in Boston and it was called a Boston Massacre even though only a few people died. Branded as rebels and "put in their place" England proceeded with business as usual, and economically continued to punish rebels. Seven years later the "rebels" ruled the land.In 1790 the soldiers of Louis XVI fired on his citizens of France at Bastille prison. Within a few years they beheaded him.In 1907 the Czar's soldiers fired on their fellow citizens demonstrating for food. In 1917 the Czar was deposed, later executed and the Communists ruled Russia.In 1979 the Shah of Iran fired on his people demonstrating for changes. He was deposed and exiled, replaced by an Islamic religious state.In 1989 Chinese Communists fired on citizens demanding more freedom.2009 China has an emerging middle class and has become the leading capitalist nation in Asia, and soon the world.
I am sure history can also show examples where the state survived attacking its people, but these are examples when the gamble resulted in the state ceasing to exist after the ominous decision to kill its own. After such a decision nothing is ever the same.