I have not heard this brought up much since grad school, and not at all by the TV punditry, but we have numbers to argue that economic performance tends to be stronger for everyone under Democratic administrations. I have linked to several postings on these studies here, here and here. More such analysis is readily available.
This piece from the Federal Reserve Bank of San Francisco finds no statistically significant advantage for either party with regard to stock market performance, an area where Republicans are assumed to be stronger. In an election year like this one, Republicans do not need investors to hear that sort of thing, especially as corporations have found Democrats to be just as willing to let themselves be twirled around lobbyists' fingers like Sauron's rings. Why would investors necessarily want to support Republicans under those circumstances?
This link, along with this, finds that Republican administrations are better for the average pocketbook during election years only, offering an explanation as to why no-growth or slow-growth Republican administrations get reelected. I doubt that Democrats have to worry about that this year.
It Is Accomplished - As Gandhi never quite said, First they ignore you. Then they laugh at you. Then they attack you. Then you win. I remember one of the first TV debates I had...