Comparative theocracy: The problem with Christian Theocracy

I've received a bajillion and two comments, emails, and IM's with questions/misunderstandings/general ignorance about comparative theocracy. So I'm going to do a series on what Jewish, Christian, and Muslim (Sunni) theocracies really look like, and the modern issues involved in each. Because I enjoy picking on Christians, and because this section is the easiest, I'm going to start here.
Judaism has the frameworks of how to build a viable theocracy (although it currently doesn't have one). The Jewish theocracy runs under a king and a religious court (the Sanhedrin or Beit Din Ha'Gadol). [There are actually two sanhedrins, the greater and lesser, but let's keep this simple, this one is an explanation to Christians, I'll go into more detail later when I discuss Jewish theocracy]. The Beit Din Ha'Gadol fills the legislative and judicial roles. All laws and judgments are derived based on the Torah (the oral Torah and the 613 of the written) and the rulings of earlier sages (although sometimes later judges will disagree with the earlier judges), and in all cases, the majority decides. The Oral Torah will get its own article eventually, when I get around to it. Donating using the paypal button on the side greatly increases the probability of me writing it sooner than later. Commenting also helps because I see people are reading what I'm writing. Anyway, back to the topic at hand: comparative theocracy.
Muslim courts also have a way to derive law. Muslim governments are under a caliph chosen for his knowledge and goodness. The courts rule and issue fatwas based on the precedents set in the Qur'an, hadith (sayings and actions of the Prophet Muhammad [saws]), and the consensus of other scholars, current and past. The madhab (school of thought) you subscribe to dictates the relative importance given to each of these categories and the credence you give to the narrators of various hadiths.
Christianity, especially Protestantism, lacks a way to derive jurisprudence. The problem stems back to the very earliest days of Christianity. The Christians tried, it seems, to have the apostles serve as a sort of Sanhedrin, deriving their rulings from existing Jewish law in combination with the teachings of Jesus and the prophecies of the Jewish prophets. An issue that faced the early church was whether or not gentile converts had to first convert to Judaism to be saved. Acts 15 reports the debate that went on among the apostles. In the end, they decided to write a simple letter to the gentile converts explaining their obligations as Christians:

²³And they wrote letters by them after this manner; The apostles and elders and brethren send greeting unto the brethren which are of the Gentiles in Antioch and Syria and Cilicia.
 ²⁴Forasmuch as we have heard, that certain which went out from us have troubled you with words, subverting your souls, saying, Ye must be circumcised, and keep the law: to whom we gave no such commandment:
 ²⁵It seemed good unto us, being assembled with one accord, to send chosen men unto you with our beloved Barnabas and Paul,
 ²⁶Men that have hazarded their lives for the name of our Lord Jesus Christ.
 ²⁷We have sent therefore Judas and Silas, who shall also tell you the same things by mouth.
 ²⁸For it seemed good to the Holy Ghost, and to us, to lay upon you no greater burden than these necessary things;
 ²⁹That ye abstain from meats offered to idols, and from blood, and from things strangled, and from fornication: from which if ye keep yourselves, ye shall do well. Fare ye well.

In summary, the gentile converts to Christianity were give three rules: Don't eat meat sacrificed to idols, make sure the meat is slaughtered by having its throat cut, not by strangulation; don't eat blood; and don't fornicate. Pretty simple. This is a good basis for a Christian theocracy to work from; a court considers options, includes the teachings of Jesus, the law of Moses, and when all else fails, direct divine revelation in the form of visions. This could have been the beginning of a Christian theocracy.
Insert Paul.
Paul writes to the Corinthians in 1 Cor. 8 that actually, it's ok to eat food sacrificed to idols; it's just that some people have a weak conscience. So as not to offend people with a weak conscience, don't eat the meat in front of them, but otherwise it's ok, no big deal. You can go to the grocery store and buy meat that was sacrificed to an idol, as long as you don't tell anyone. But in the same letter he upholds another of the four simple rules: in 1 Cor. 5, he lamblasts a couple who are husband and wife, but used to be son and step-mother. So apparently, the meat part isn't that important, but the fornication part is. Or is it? How can one be sure? According to 1 Cor. 8, basically anything goes as long as your conscience is ok with it. The rules given by the legitimate apostles can apparently be ignored; if they can be, what else can be? The problem is obvious today. Some of the laws of Moses are considered valid; others aren't because Christians claim to be under the "new covenant". Which ones are and are not valid? Apparently, the individual should be guided only by his conscience. This freedom of the individual to make and break laws as he sees convenient means that there can be no true Christian theocracy. In Judaism and Islam, if crazy judge X rules that X is permissible, but the majority of the scholars disagree with him, crazy judge X is discredited and his ruling can be ignored. In Christianity, crazy judge A has as much right to make a law as any other judge And that is the problem with Christian theocracy.