Just weeks before Blackwater guards fatally shot 17 civilians at Baghdad’s Nisour Square in 2007, the State Department began investigating the security contractor’s operations in Iraq. But the inquiry was abandoned after Blackwater’s top manager there issued a threat: “that he could kill” the government’s chief investigator and “no one could or would do anything about it as we were in Iraq,” according to department reports.
That's why competition is important in the market for security. Without competition, a single supplier becomes a monopsony, which is as bad as a monopoly.