Andrew Samwick says the Republican presidential candidates have been almost invisible in New Hampshire this year. He's got a few possible explanations for this, but even so, I find this pretty interesting:
It is surprising how little role that money is playing in this contest. The top candidates are not spending money on large media buys. Television advertising has not been overwhelmed by political ads. An unmet need to raise money has not been a reason for candidates to drop out of the race and focus the remaining candidates on distinguishing themselves from each other. More generally, we are in the low-fundraising, low-spending equilibrium in which candidates are responding to weak campaign efforts by their opponents by conserving their own resources, including their time and travel. That won't continue to be the case later in the primary season, but it is certainly the case now.
Fundraising has been pretty sluggish for all the Republican candidates this year, and apparently that's not changing. What's more, Iowa seems to be sucking up everyone's attention to a surprising degree. For the first time in decades, nobody cares about New Hampshire.