I've heard some people say, people dear to my heart and who I respect to a degree that makes me sad to hear them say it, that what we need in the US is a good old-fashioned Theocracy. I've seen this idea run the gamut from those who want to implement the Judaic law found in the Torah to those who want American law to reflect "conservative, traditional biblical family values." To the first I'll not even give the credence of a rebuttal; the very idea that implementing a law, designed for an ancient nomadic people, to which we are not morally bound as Christians, and which Christ himself declared moot is beyond ridiculous. I'd like to address, instead, the more mainstream and slightly-less-offensive idea that American law should reflect and legislate those"conservative, traditional biblical family values."
First of all- who, exactly, gets to define what those values are? Not even conservative evangelical Christians have a uniform moral ethic, a uniform theology, or even a uniform or consistent biblical hermeneutic. If any one facet of Christianity were to make the rules, other, equally "conservative" facets would be bound to a framework with which they would not agree. Take, for example, the abortion issue: I personally know conservative, evangelical Christians who believe that no abortion is ever right, not even to save the mother when the alternative is the death of both mother and child. (I find this position personally abhorrent and dehumanizing, by the way) Others are passionately in favor of allowing for it only to save a mother's life from being sacrificed unnecessarily; still others think that in the case of rape or incest a woman should have the right to abort. In a theocracy, the "right" view is generally inseparable from the "legal" view, and once a "right" position is codified by those in power, the dissenters are expected to acquiesce. Thus, one of the problems with theocracy from the beginning would be its limiting of religious freedom, even among the "conservative, traditional American Christian" subset.
Secondly- what is the benefit to legislating extra-biblical morality? Make no mistake; the "conservative traditional values" mores often encompass far more than is required of New Testament believers. Some examples include rigid gender roles, male leadership, "purity" that goes beyond abstaining from sex with those to whom you're not married into the realms of "emotional purity" and that ilk, arbitrary standards of appropriateness in language, demonizing divorce, maintaining a "Sunday" list of do's and don'ts in an attempt to return to a concept of sabath keeping, and many more. From from being beneficial, I seem to recall Jesus having some rather harsh things to say to those Jews who imposed restrictions on others far in excess of that which the Torah mandated. What if you're gay? Divorced? What if you're a woman with leadership, apologetic, or pastoral skills? In this sort of society, if you don't meet the traditional nuclear familial ideal and fit well into your gender role you are on the fringes at best.
Most troubling, though, is the fundamentally flawed theology/philosophy which allows for Theocracy/Ecclesiocracy as a valid and morally superior option. In more libertarian forms of government, the focus is on either protecting the rights and freedoms of all citizens and by default punishing those who harm their neighbors, protecting the good of the society at large, etc. In an Ecclesiocracy or Theocracy, however, church law and civil law are inextricably linked and religious prohibitions are made law whether or not they make sense in the secular world, are generally beneficial, or meet the same standards of good and harm that laws in a non-religious, libertarian legal framework would need to meet. Proponents of a theocracy generally believe that there is good to be attained by legislating religious morality beyond the protection of basic freedoms and those who cannot protect themselves. In other words, this view hinges on religious observance, which is executed because the law says it must be so, being of personal and social benefit. This view I disagree with wholeheartedly. Social benefit comes from laws which protect the innocent, basic rights, etc to be sure; I see no social benefit to be derived from dictating observances that do not harm others but rather encroach on my personal and religious freedom. Here's the worst part- this view implies that doing right things, or following right laws, makes you right with God. That is false. All the right things, done because the law says we have to, mean nothing to Jesus. Depending upon the item in question, doing it may make us a "better person", and may make our society more pleasant; but I am convinced that obeying God means nothing if it is not voluntary. We are commanded to do justly, love mercy, and walk humbly. We are never told to look to the government to tell us what that means.
Also, I think that the very protection of innocence and freedom is better served by a more unbiased, libertarian form of government than by a theocratic one, because it operates with less prejudice and far more objectively. Another flaw in theocratic government is that, if religious leaders are also civil leaders, then to question civil leaders is to question religious leaders and sometimes questioning religious leaders is equated with questioning God. Absolute power corrupts, and any leader who is above questioning and accountability can be tempted to abuse their power.
Really, any system that conflates questioning civil things with questioning Christianity and God's will is a very dangerous thing.