The power of the State—of government, in other words—is awesome. And nowhere is that power greater than when it controls life, death, and liberty. The Framers knew this kind of power can corrupt and believed in the principle, articulated much later by Lord Acton, that absolute power corrupts absolutely. They also believed that such power could be grossly misused in the hands not just of individuals acting on behalf of the State but also on behalf of the majority population, creating, in the words of John Adams, "tyranny of the majority." The whole constitutional structure, and the civil liberties built into the first 10 amendments to the Constitution, are grounded in those beliefs.
That immense power over liberty and life is especially evident in the criminal-justice system, in the hands of police and prosecutors. The deep suspicion of governmental power that animates not just the Framers but also philosophical conservatives demands a vigorous effort to curb that power and provide the necessary and appropriate checks and balances to the police and prosecutors who wield it. That effort has rarely been there, with notable exceptions in the libertarian world that I will discuss below.
Why? One main reason is that conservatism has another strain: of intense respect for the existing order, a fear that it can be undermined by crime or disorder, and the belief that police and prosecutors are the front line of protecting that order. Another reason is that the abuses of power are most harmful to those who are weak, limited, and poor, and disproportionately minorities. There is a racial element here, but one does not have to be racist to believe that arrests or traffic stops by police, or stop-and-frisk policies, only occur where crimes have been committed or there is real and reasonable suspicion of same—and that if one is not guilty, one will either go free or suffer the indignity of an undeserved traffic ticket; no big deal. That bigger indignities are suffered by the poor and minorities doesn't resonate for those who have never experienced the problems.