Most legislators - including much in the governor's own...

[MadeleineK361]

"Most legislators - including much in the governor's own party - realize that the governor's budget would imperil the state's finances, nonetheless, the budget is likely to be approved, because few legislators want to anger voters by cutting spending or raising taxes."

The All the Verbal book says a proper way to rewrite this sentence is as follows:

Most legislators - including many in the governor's own party - realize that the governor's budget would imperil the state's finances; nonetheless, the budget is likely to be approved, because few legislators want to anger voters by cutting spending or raising taxes.

I do not understand why there should be a comma before "because." The comma seems superfluous and does not clarify any meaning. The question stem in this exercise provided a box around the ", because" (including the comma), so it appears the authors clearly considered the placement of the comma in formulating this question.

Any guidance on why the comma is accurate would be much appreciated.

[Sage Pearce-Higgins]

This is a simple answer: it doesn't matter. Commas have lots of functions in English, such as to mark off modifiers, to show lists, to separate clauses, or even just to break up a long sentence with a "breath". GMAT doesn't test comma use as it's too controversial. Sure, we can get some clues from the way GMAT uses commas - they follow the Oxford comma convention, use a comma before 'which', etc. - but we're never expected to eliminate an answer choice based on a comma. I agree with you in this case that the comma before 'because' seems unnecessary, but it's no big deal.