The term "Common Law" has several meanings or derivations. In its most important sense, it means what are (or should be) the most common or universal laws all over the world despite the different laws in different countries or the different laws and rules that different religions impose on their followers. This is why Common Law must be secular to be truly neutral, universal, and common.
This may trouble some people who feel that Common Law means the common legal traditions of their favorite country, culture, or religion. However, restricting it so would make it less common with the rest of the world and thus defeat its highest purpose. Remember, the highest goal of true Common Law is to figure out what are the minimum universal common principles (MUSTs) that people must live by in order to have a functioning civilization, without the extra laws and customs (SHOULDs) that are specific to particular countries or religions or cultures. If you've read most of this web site, it should be quite obvious that the answer is the Non-Aggression Principle (NAP). Thus, throughout this web site, the phrase "Common Law" will be considered to mean NAP. This is what Common Law should really mean, and the world would be much better off if was truly the common (and only) law of the whole world.
There are those, however, who still want Common Law to mean only the larger set of laws and customs specific to their own heritage, and don't care what would really work for the rest of the world. For example, many American conservatives think in terms of English Common Law and consider America to be a "Christian nation" or one founded upon their own conservative view of Christianity. This is only partly correct, to a small extent, in that some of the Founders were Christian and some didn't think much about other religions. Some of these may even have thought of religious freedom only in terms of Christian denominations, others in terms of all three of the main group of monotheistic religions (Judaism, Christianity, and Islam), fewer still in terms of any religion that believes in what they would've recognized as some sort of god or supreme being, and even fewer that would've included Atheists and Agnostics. But fortunately, enough of the Founders had more varied religious backgrounds and were more broad-minded and realized that freedom of religion must include all religions, as well as none, and must include freedom from religion, and separation of Church and State. That is why, for example, the generic term Creator was used in the Declaration of Independence, so that it could mean different things to different readers yet still retain a common logical meaning for all, in supporting the fact that each individual's inherent rights are part of his very nature and not granted by governments or other individuals like privileges which could be taken away. Other language in our founding documents included religious sentiments of the various authors, but the crucial points and ideals were phrased more generically whenever the author thought to do so. And while some authors habitually thought in terms of a Christian context and wrote accordingly, the vast majority of our Founders would have reconsidered and written more generically if they had had an opportunity to discuss the matter with our leading libertarian thinkers in our modern times which embrace more religious diversity. The bottom line is that America was founded upon NAP, not "Christian principles" - to the extent that the latter apply, it is only the extent to which they themselves (e.g. the civil portion of the 10 Commandments) are based on NAP.
While some Christians waste time citing a handful of quotes to try to dispute this, there are many more or better references (including the Treaty of Tripoli) to refute them, too many to list here. An excellent (but long) article by Christian political writer Joel Skousen explains why it is God's will that government should be secular, and as another Christian patriot said, real Christians do not want to govern non-Christians, only themselves.
If you read all the above, including the links, and that still doesn't convince you, then this thought should get right to the heart of the matter and will probably shock many conservative Christians: Jesus was a libertarian.