Canada and the United States share the world’s longest international border. For those living in the immediate vicinity of the Canadian side of the border, the events of 9/11 were a turning point in their relationship with their communities, their American neighbours and government officials. Borderline Canadianness offers a unique ethnographic approach to Canadian border life. The accounts of local residents, taken from interviews and press reports in Ontario’s Niagara region, demonstrate how borders and everyday nationalism are articulated in complex ways across region, class, race, and gender. Jane Helleiner’s examination begins with a focus on the “de-bordering” initiated by NAFTA and concludes with the “re-bordering” as a result of the 9/11 attacks. Her accounts of border life reveals disconnects between elite border projects and the concerns of ordinary citizens as well as differing views on national belonging. Helleiner has produced a work that illuminates the complexities and inequalities of borders and nationalism in a globalized world.