The campaign to re-elect President Donald Trump is officially underway in New Hampshire.On Saturday morning, a Trump field office opened in Manchester, with volunteers welcoming back in-person campaigning.Corey Lewandowski, Trump’s 2016 campaign manager, was among those who addressed the crowd.“We're going to see the president and the vice president coming up here on a very regular basis,” said Lewandowski, now a 2020 Trump campaign senior adviser. “There are only a few real battleground states in the country. New Hampshire is one of those, and it's a place where we know the core principles of what Donald Trump has talked about – smaller government, lower taxes, less regulation, strong military.” Trump just recently resumed his campaign rallies.