Reading Comprehension

Hello,
I came across a question in Sentence correction .Take a look at this , and please tell me what to use ("who" or "whom"?)


A recent decision made by the United States Attorney for the Southern District of New York, WHO many consider a leading contender for a cabinet appointment, is both seen by most legal observers as a savvy political maneuver and an abrogation of professional responsibility

Or

A recent decision made by the United States Attorney for the Southern District of New York, WHOM many consider a leading contender for a cabinet appointment, is both seen by most legal observers as a savvy political maneuver and an abrogation of professional responsibility

Please tell me what to use.

I generally follow a strategy for finding out who / whom usage, but it doesn't work here.
My method is to replace "who" with "he" and see if the sentence still makes sense and to replace "whom" with "him"(singular) or "them"(plural).For example,consider the following sentences.

I wonder who is in charge.
This sentence is correct . "He" is in charge. This is also correct.

Mr X was with whom ? This is correct. Mr X was with him. This is also correct. But "Mr X was with he"
is wrong.
I have just replaced "who" with "he" and "whom" with "him".

But this method does not work for the ORIGINAL example.
Please tell me a way to find out when to use who/whom ?

This is a very good method. You could use this method also with the example above, only you would have to change the word order in the sentence.
Do we say "consider HE" or "consider HIM?" I think now you will be able to choose the right option by yourself.

Yes..
It works.
Thanks for the reply