Q:

Subjunctive use in that-clauses

Which is the better style of writing a "that-clause" using "insist"? Is option a the most accepted form of subjunctive usage?
a. He kept insisting that I not blame them.
b. He kept insisting that I must not blame them. 

A:

Both are grammatically fine.  The "must" in B is superfluous and removes the subjunctive form; however, both are correct.  I would personally say and write letter A; however, I do not think that either one is wrong.  
Somebody suggested inserting "do" and making what is called a periphrastic subjunctive such as in his example, 

"He kept insisting that she do not blame them."

Shakespeare used to use periphrastic subjunctives such as when he said, 

"If he do bleed..."

but the form is very uncommon in Modern English.  I would not use it, but I can't say it's completely wrong.  

