Which states does or does not get a representative is not a straightforward process. This wikipedia page explains it pretty well. But a simple way to think of the situation is this: Main currently has more population than New Hampshire, Hawaii, and Rhode Island, other states with two representatives. In order for Maine to drop to one Rep. either it would have to fall behind those states and be next to Montana or else other states like Texas, Arizona, and Florida would have to gain population so quickly that it first takes away the representatives of those states before Maine loses one. Make sense?