Why no subject after “as”?

Question

1. Please correct me, but does as function as a conjunction here? I already tried i, ii, and iii.

Page 3: In any event it might be said that Hart ‘won’ the debate in the sense that it was his infl uence that led to the passing of the 1960s legislation liberalising the law on abortion, prostitution, homosexuality, and abolishing capital punishment. However such issues can still arise – as was seen in the Brown case, considered later, and the ongoing issue of the ‘rights’ relating to assisted suicide...

2. Why no subject here? Isn't the subject such issues, which implies "such issues can still arise – as they were seen in the Brown case..."?

Page 43: ...the new coalition Justice Minister is the extremely experienced MP Kenneth Clarke QC, although his experience may not save the legal system from the consequences of the comprehensive spending review, as was made only too evident in the announcement in November 2010 that the whole of the civil legal aid system was to be fundamentally restructured, not to say cut (see further at chapter 14 below)

(Question 3 has been posted separately) 4. Why no subject here? What'd be the subject?

5. Are there any terms that describe the ideas or issues in this entire post?

Source: The English Legal System 2012-2013, Gary Slapper. I myself bolded and italicised.

Answer 1

1. You may call as a subordinating conjunction, as is the case in traditional grammar, or a preposition, as is the case in CGEL. It doesn't really matter what you call it.

2. The subject of the as clause is not such issues but the entire superordinate clause. What was seen was not the issues but their arising. You might paraphrase

   That such issues can arise was seen in [&c] OR
   In [&c] it was seen that such issues can arise.

   An explicit subject within the subordinate clause is not required; when an explicit subject is absent the construction is understood to take a preceding clause or constituent as its subject. The same phenomenon may be observed with other constructions:

   1.Bill wants Susan to go to the party.
   2.Bill wants to go to the party.

   In 2, Bill is the subject of both want and go, so we do not need to say Bill wants Bill to go to the party.

3. The verb is singular because its subject is singular.

4. In the 'p.43' quotation, likewise, the subject is the preceding clause his experience ... review. What was made evident was the inability of Mr. Clarke's experience to save the legal system.

5. These are comparative constructions (like as...as, same...as, such...as) of a special kind: the initial as or same or such is omitted because what is being compared is things which are equal. The phenomenon expressed in the head clause is 'like' or the same as what is seen or evident (or, in my 1., the case) in the subordinate clause.