Would it help to pressure candidates' campaign committees directly during primary season?

It seems to me that regardless of who wins the Democratic nomination for 2016, we will have to be on them from Day 1 if they win the general election. No honeymoon, no immediate trust that the job is done now that they have been elected. Just constant vigilance.

But I was thinking that perhaps we could start much, much earlier. If we were constantly calling and writing the campaign committees of Hillary and Bernie and whoever else runs, the primary season might look different and our nominee might act differently.

Did anyone here do this during 2008, and if so, how did it work out?