In both politics and business you can get a disproportionate size of an audience by being the first to react to an event or trend.
The Democratic Party have put out a video response within a day of the Republic candidates’ debate.
It’s not polished, but it doesn’t matter, as the message is so well crafted that it will resonate with voters regardless.
(hat tip @ciaranward)
politicaladvertising.co.uk 
The Republicans are running their own rather negative advertising campaign called “Change Direction”, so far they have created four short videos:
They are all fairly repetitive and I don’t know how effective they are at getting their negative message across.