Indiana Gov. Mike Pence (AP Photo/Alex Brandon)

Every once in a while, a controversial state bill gets a boost in attention and becomes the focus of a national debate. It happened with California’s Prop. 187 in the 1990s, and with Arizona’s SB 1070 in 2010 (both were about immigration). It may be about to happen again with a law in Indiana that Governor Mike Pence is about to sign involving gay rights and “religious freedom.”

Since we’re at the start of the Republican presidential primary campaign, this issue could become a way for candidates competing for the votes of Christian conservatives to try to distinguish themselves. Here’s what’s happening:

Indiana Gov. Mike Pence is set to sign into law a measure that allows businesses to turn away gay and lesbian customers in the name of “religious freedom.”

The bill has sparked an uproar among gamers and church groups that hold their conventions in Indianapolis and businesses that are threatening to pull out of the city.

Even the NCAA — which is less than two weeks from hosting its men’s basketball Final Four in Indianapolis — was critical, saying the organization is “committed to an inclusive environment where all individuals enjoy equal access to events” as it hinted the bill could damage the city’s reputation as a host of major sporting events.

The gamers in question are the organizers of Gen Con, a yearly video board game convention held in Indianapolis. In response to the bill, they are threatening to move the convention elsewhere. The Disciples of Christ, which was scheduled to hold its General Assembly in the city in 2017, is also reconsidering.

The Indiana bill is part of a wave of recent legislation seeking to guarantee “religious freedom” on the part of organizations or businesses who want to retain the right to discriminate against gay people. While the advocates usually posit a baker who doesn’t want to have to take business from a gay couple seeking a wedding cake as the person the law would protect, the laws are often written so vaguely that they would allow almost any kind of discrimination, so long as the discriminator justifies it on the basis of their religious beliefs.

The bill in Indiana doesn’t mention words like “gay” at all. It merely says that the government can’t “substantially burden a person’s exercise of religion.” And a key element of the conservative Christian argument about religious freedom is that “exercise” of religion isn’t just about rituals and prayer and worship; it extends to everything, including commerce.

The implications are therefore enormous. Forget about the baker — what if you own a restaurant and think homosexuality is an abomination, and therefore you want to hang a “No gays allowed” sign in your window? Under this law, you’d be able to. Or what if you’re a Muslim who owns an auto repair shop, and you want to refuse to serve women, because you say your religion tells you that women shouldn’t drive?

Those kinds of concerns are what led former governor Jan Brewer to veto a similar bill in Arizona, after she got all kinds of pressure from the state’s business community, which feared boycotts of the state. That same pressure has been building in Indiana, though it doesn’t seem to have moved Governor Pence.

The more news this Indiana law gets, the more likely it is that it will become an issue in the presidential primaries. And it fits neatly within the key divide among Republicans: on one side you could have business groups that are nervous about negative economic impacts and strategists who don’t want the GOP to be known as the party of discrimination, while on the other side you have candidates eager for the votes of religious right primary voters.

I have no doubt that candidates like Ted Cruz, Bobby Jindal, or Mike Huckabee will rush to support the Indiana law. The real question is what happens with the candidates who want to get as much support as they can from conservative Christians, but also want to appeal to the more moderate voters (and funders) who may not be so pleased with these kinds of laws. Those candidates also surely know that general election voters will be much less favorably inclined toward this law, and that it could well fit into a broad theme of Republicans as intolerant, not only on issues affecting gay people but on immigration as well. If you’re Scott Walker, Marco Rubio, or Jeb Bush, this could be a very tricky issue to confront.