How to parse this sentence and how to understand ため?


I was trying to read [this editorial](http://editorial.x-winz.net/ed-73463)
and I am really wondering how I should understand the following sentence.

>
> 露骨な介入の背景には、１０月の党大会を控えて権力基盤を強めたい思惑もあろう。｛｛江沢民{こうたくみん}政権時代の既得権益層が｛今も力を持つとされる｛石油や電力などの｝業界｝｝が、習{しゅう}指導部に忠誠を示すかどうかの判断材料とする｝ためである。

Here is how I understand it, I included in parenthesis the word or group of
words I tried to translate.

> In the background of this open intervention, reinforcing the basic
> prerogatives seems to be a desired intention (思惑) of the upcoming (を控えて) one
> party big meeting to be held in October. That is because (ため), the fact that
> whether the electric and petroleum industry, which were regarded as powerful
> under the Jiang Zemin (江沢民{こうたくみん}) leadership and still are (regarded as
> powerful), will show their allegiance to the Xi leadership (習{しゅう}指導部) or
> not will serve as decision material.

I have real difficulties with how to render 思惑 in the first phrase, I am not
sure to understand well を控えて and above all I can't make head or tail of ため in
the last sentence. The best I can think of is that ため goes with and explain
the first sentence that ends with あろう. But all of that is just mere
suppositions so I would be very grateful to anyone who could clarify this
excerpt.




In short, 露骨な介入 is for the purpose（ため）of using it as criteria to judge if the
electro or petro industries obey to Xi.




In short, 露骨な介入 is for the purpose（ため）of using it as criteria to judge if the
electro or petro industries obey to Xi.

