I was recently briefed by a Border Patrol Agent who told me that a NEXUS card works a lot better than even a Passport to travel to and from Canada, Mexico, and most of the Amarica's. He said it even will help speed you thru Homeland Security checks during domestic flights. And he said the best thing is the cost is only $60 compared to the cost of a Passport.
Of course this was one agents opinoin so please check into it before making any decisions.
In Michigan and I believe other border states we have the option of getting an Enhanced drivers license which allows us to reenter the US from Canada and Mexico if traveling by a vehicle.