MANCHESTER, N.H. — Rick Santorum's New Hampshire experience is far different than his Iowa experience.

The one-time long shot candidate who ran his grassroots-focused Iowa campaign on a shoestring nearly beat Mitt Romney in last week's leadoff caucuses. That distinction led to overflow crowds in New Hampshire, reportedly booming fundraising and, it seems, a host of new challenges for both the campaign and the candidate.

It's clear that his stripped-down campaign isn't used to the spotlight or prepared for the newfound interest.

At times, the candidate himself seems to struggle with the demands of being near the top of the pack instead at the back of it. Tuesday's primary may determine whether Santorum remains in the spotlight or returns to obscurity.