The freedom to marry is a fundamental right that should not have to be won or defended at the ballot box. In fact, ballot initiatives are a bad way to write or rewrite laws of any kind. Unfortunately, that is the reality of American politics, which is why same-sex marriage measures on the Nov. 6 ballot in Maine, Washington, Maryland and Minnesota could turn out to be pivotal in the struggle for marriage equality.

Thanks to court rulings and legislative victories, same-sex marriage is now legal in six states and the District of Columbia, and polls show that a majority of Americans support the legalization of marriages for gay, lesbian and bisexual couples. But same-sex marriage has never won a ballot referendum.

The measure in Maine probably has the best chance of winning. Three years ago, Maine voters rejected a marriage-equality bill that had been approved by the State Legislature. But, instead of giving up, supporters of the freedom to marry went right back to knocking on doors, raising money, honing their arguments and organizing for a new vote this fall to legalize same-sex marriages.

Although recent polls of likely Maine voters are encouraging, the outcome is still far from certain. Historically, polls on such ballot tests have been misleading, and anti-marriage forces are waging a loud propaganda campaign. They are running television commercials suggesting that marriage-equality opponents would be unfairly “fired, sued, fined and punished” if the referendum passes, and that it is possible to treat gay and lesbian couples fairly while still excluding them from the right to marry. It would help if the state’s two supposedly moderate Republican senators, Susan Collins and Olympia Snowe, who is retiring, would stand up against forces of intolerance within their party by publicly supporting the referendum.