Does 以安倍的自民党为首的联盟 use the 以 ~ 为 pattern? According to the following sentence:


  日本一家电视台的民调显示，以安倍的自民党为首的联盟将保持三分之二的“绝对多数”，与安倍九月份解散议会下院之前的比例相当。


The bold sentence starts with 以, and it also has 为. So at first I assumed it is 以～为 pattern, which is "regarding A as B" or "taking A as B" in English.

However, I also found that 为首 means "serve as the head", and it should exactly refer to 安倍. And I understand the meaning then.

So is this sentence 以～为 pattern or not? If not, what does the leading 以 mean and work in this context?
Yes, [以][安倍的自民党][为][首][的联盟] fits the pattern of [with][A] [as] [B] 

"首" is short for "首领", 

[A - 安倍的自民党] = [B - 首领]


'为'+'首(领)' simply means 'as leader' (preposition + noun)
'为首' as a set phrase, is a common adjective "leading/ top ranked" 


Example:

'在这次会议上, 为首官员是北京市长'-- 'In this meeting, the leading (top ranked) officer is Beijing mayor'