Are the views of voters that have been manipulated by well-heeled campaigning and advertising as "democratic" as voters' original views?
Yes, these views are democratic. The wording of the question implies that voters cannot make up their own minds. It implies that advertisements can “manipulate” the voters as if the voters are incapable of thinking for themselves.
If we give voters credit, we can see how their views are still democratic. Voters are exposed to ads from both candidates or sides of a campaign. They can evaluate the arguments made by the various ads and decide which they find more compelling. There is no reason to think that this is undemocratic.
We would not want voters to make up their minds without being exposed to arguments from both sides. Therefore, we should want campaign ads that give voters information and allow them to decide. This is clearly democratic.