what the hell is it talking aobut?

好象缺少比较对象。

The structure should be like this,

elements do nowhere more closely than (sth should be here)... in relation to ... as to ... in which ...

是否可这样看：

the religious and experiential elements (in the legal development of Polymouth) do merge  nowhere more closely than <the religious and experiential elements (in the legal development of Polymouth) do merge省略>  in relation to the colonist idea {as to the form [in which law was to be expressed(, in either seemingly unprecedented enthusiasm for the lex scripta,) for codification.]}

即：the religious and experiential elements （in the ...）do merge  most closely in relation to the colonist idea {as to the form [in which law was to be expressed(, in either seemingly unprecedented enthusiasm for the lex scripta,) for codification.]}

意思是说：就法律规范化表述的形式而言，宗教和经验因素，在其与殖民地理念的互动关系中，才融合得最为紧密。

我只是望文生义而不知所云。

我连中文都看不懂。

反复看三遍， 觉得wangyu大哥讲的对。

I would suggest that to analyze the sentence in the way following:

the religious and experiential elements in the legal development of Polymouth merge more closely (in relation to) NOWHERE than in relation to the colonist idea [as to the form in which law was to be expressed], (in either seemingly unprecedented enthusiasm for the lex script, (or) for codification.)

翻译：在polymouth法系的发展中，就法律的表达形式而言，宗教和经验的因素和殖民思想的关系最紧密。（这个紧密的关系表现在对法律条文和法典的前所未有的热情上）

似乎还没有定论，帮顶！

让更多的朋友上来发表意见！