The current nominating calendar could also help ensure that social issues stay in the mix. Immediately after the four early states go — Iowa, New Hampshire, South Carolina and Nevada — a batch of very conservative Southern states are moving to schedule their primaries for March 1, including Georgia, Tennessee, Arkansas, Mississippi and Alabama. Republican base voters in these states may likewise demand a candidate strongly opposed to same-sex marriage.

An adviser to one of the more establishment-oriented candidates said that people who are most worked up about gay marriage won’t vote for Bush, Romney or Christie, anyway. The real fight is going to be among the social conservatives trying to outdo one another in being against gay rights. This adviser hopes that the race to the right among the social conservatives will help drive independents and donors toward a candidate who takes a more conciliatory tone.

Evangelicals say the debate about gay marriage will be closely linked with discussion about religious liberty, in essence protecting the freedom of those who oppose gay marriage to not recognize such unions. The most prevalent example is the baker who does not want to make a wedding cake for a gay couple because of his religious exceptions.