A grammar problem

Today’s political candidates may reach wide audiences by appearing on television,but old-fashioned barnstorming still has value because it allows the electorate to meet candidates face to face.
The orrigional problem is asking you to indicate whether the underlined part is grammartically correct,the answer turned out to be yes,but can anybody explain?I thought the correct form should be:
Today’s political candidates may reach wide audiences by appearing on television,but old-fashioned barnstorming still has value in allows the electorate to meet candidates face to face.

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Sorry, CG, but the original is right and yours is wrong-- but if you change your ‘in’ to ‘in that’, you will have formed a nice alternative way of expressing the original:

Today’s political candidates may reach wide audiences by appearing on television, but old-fashioned barnstorming still has value (because / in that) it allows the electorate to meet candidates face to face.’

As to why the original is correct-- ‘because’ is a common subordinating conjunction serving its purpose (expressing reason) appropriately here-- and that’s really all there is to it:

‘Barnstorming has value because it allows intimacy.’
‘Oreos are good because they contain lots of sugar.’
‘I like you because you are cute.’

(‘In that’ will work in these examples too, but ‘because’ is much the commoner conjunction.)

(PS: Oh, and I forgot to mention that your subject line should read ‘a’ not ‘an’ grammar problem.)
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That sounds OK to me, CG.
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