MESA, Ariz. — Among the customers browsing the light-infused Jesus paintings and spiritually tinged volumes of a Mormon bookstore here, you will find some of Mitt Romney’s most passionate supporters. But don’t expect them to go starting a “Mormons for Mitt” group anytime soon.

Mormons, one of Romney’s most loyal voting blocs, are often quiet about their support. That might be because the church discourages political involvement. But Mormon voters also describe another source of personal reticence — the danger they see in associating Romney too closely with his faith.