Following just after the pepper spray cop, James Fallows, writing at The Atlantic, is shocked to find the police have been militarized — Turning Patrolmen Into Soldiers: How Did We Let This Happen?. It points to the article from early November, How the War on Terror Has Militarized the Police:

Ever since September 14, 2001, when President Bush declared war on terrorism, there has been a crucial, yet often unrecognized, shift in United States policy. Before 9/11, law enforcement possessed the primary responsibility for combating terrorism in the United States. Today, the military is at the tip of the anti-terrorism spear. This shift appears to be permanent...

In an effort to remedy their relative inadequacy in dealing with terrorism on U.S. soil, police forces throughout the country have purchased military equipment, adopted military training, and sought to inculcate a "soldier's mentality" among their ranks.

Fallows has a brief follow up too, Tanks in Small Towns, where he adds "the militarization of the police perversely ignores the way the real military is evolving".