Re: Shooting the messengers much?
Whether the advertising, whether flyers, mailed, tv/radio, or internet actually has much effect is something about which I suspect many in the advertising business might well be loath to discuss in depth. Advertising volume probably is not a good indicator of effectiveness.
Advertising probably is an effective way to provide notice of new or redesigned products or services, and some of the same effect may exist in politics, especially for first time candidates and lower offices, but long-standing political leanings are quite tightly bound in various ways to who we are and how we perceive ourselves, others, and the world. They are a lot harder to change than preferences for utility items and consumables. That, among other things, is a basis for the reaction to Cambridge Analytica and social media, both to campaigners who used them and the targeted recipient class. I suspect both the optimism of the former and the horror of (some of) the latter greatly exceed the actual effect, especially when one considers that all major candidates use much the same techniques and the net effect likely will be small. In the US 2016 election, the shocked, but very extensive and free media coverage probably benefited Trump more, by several orders of magnitude, than any social media interventions, whether by the campaign or by the Russians, whose effort, while similar, was at least two orders of magnitude smaller.
The alleged Russian hacking of Democratic party and campaign organizations is much more serious, although not new or particularly unusual in US politics except for being done by a foreign government. Hacking directed at government and private sector election management organizations is more serious still, and as far as I know has not been done previously in the same way, or by foreign governments. The indictments issued today, although largely symbolic, are entirely warranted, and probably should be followed up by other actions.