According to the website for Portland, Maine, these things constitute proof of identity and proof of residence (you need both to register in your state):
What do I need to bring with me to register to vote?Picture identification and proof of residency. Any of the following may be used to prove residency.
- A direct statement of intention (a sworn oath)
- The residence address, not a post office box, shown on a current motor vehicle registration;
- The residence address, not a post office box, shown on a current income tax return;
- The residence address, not a post office box, where mail is received;
- The residence address, not a post office box, shown on any current resident hunting or fishing licenses
- The residence address, not a post office box, shown on any motor vehicle operator's license held by the person; or
- The receipt of any public benefit conditioned upon residency.
The following are examples of what are not acceptable as proof of residency:- Mail addressed to "occupant" or "resident"
- Birth certificate
- Marriage license
- Social Security Card
Source: portlandmaine.gov
Looks like photo ID is required. As these things are standardized throughout the United States at the State government level (not the local government level), this should apply to you wherever you are in the State of Maine.
If your local government keeps gives you trouble when trying to establish proof of residency with any of the above, go talk to the ACLU in your state and get that sorted because your constitutional rights are probably being infringed.
Edit: Actually, no, photo ID isn't the only form of ID acceptable under Maine statute law:
§112-A. Proof of identity for voting purposes
Any of the following forms of documentation may be offered by an applicant and considered by a registrar in verifying the identity of an applicant who is registering to vote under this chapter and whose name does not already appear in the central voter registration system as a registered voter. The registrar need not request or consider all of these forms of documentation in order to verify an applicant's identity.
1. Government-issued photograph identification document or credential. A government-issued photograph identification document or credential, including, but not limited to, a current and valid United States passport, military identification, driver's license or state identification;
2. Other government-issued identification document. A government-issued identification document without a photograph, including, but not limited to, a certified birth certificate or a signed social security card;
3. Other official documents. An official document, including, but not limited to, a document confirming eligibility determinations for public benefits, a utility bill, a bank statement, a government check, a paycheck or other government document that shows the name and address of the voter; or
4. Verified unique identifier for new voters. A verified unique identifier for new voters, including the voter's Maine driver's license number, Maine identification number or the last 4 digits of the voter's social security number that are successfully verified through the central voter registration system verification.
Source: mainlegislature.org
Go talk to the ACLU.