Montana has a population now on par with that of Rhode Island (between 1.0-1.1 million), yet Rhode Island has two congressional districts, and Montana has one. If a district needs to be cut in another state, many slow growing states are a viable option (New York, for example).
Before anyone says that this is partisan in any way, it is simply based on demography. Although Montana is a majority Republican state, other majority Republican states could lose districts, so the electoral college may not have a partisan shift.
This is likely mostly up to the states in not congress, but signing this petition could still help spread the message to the states.