Thanks, but I was not really talking about voting. Wondering how you find out if someone else is using your SSN?
Quite a few years ago, my SSN had been hijacked by an illegal immigrant. I found out several years after the fact, when the IRS sent me a demand letter for unpaid taxes. Although the person had taxes withheld, it was not nearly enough to cover the tax burden for all that marginal income.
But, as to your question, you can go to your local SS office and ask for a print-out of what has been reported on your SSN. I now do that every year before preparing my tax return.