Like many proud, East Coast WASP institutions, the Episcopal Church has lost considerable clout over the last few decades. Trinity Church, in Manhattan, is a rare redoubt of influence. Thanks to Queen Anne's 215-acre donation in 1705, Trinity is one of Manhattan's largest landholders. The church has sold some of the land and parlayed into a $2 billion portfolio, making it an exceptionally wealthy parish.

Two years ago, an internecine fight broke out over what to do with that money. Some members of the vestry, the parish's managing board, felt the church should be more activist, and many of the more passive members resigned or were forced out.

In a sign of how that fight shook out, Forbes's Clare O'Connor reports Monday that Trinity is using a small piece of its portfolio to pressure Walmart on gun sales. The church owns a token amount of stock in the mega-retailer—$2,000—but it wants shareholders to vote on a proposal that's effectively an anti-gun measure. In short, Trinity says, Walmart's board should decide whether the chain will sell certain rifles. Walmart chooses not to sell plenty of other products for moral reasons; why not guns with high-capacity magazines?

"There is a substantial question regarding whether these guns are well suited to hunting or shooting sports; it is beyond doubt that they are well suited to mass killing, and tragically more effective for the latter purpose, than are the handguns equipped to fire ten or fewer rounds that the company chooses not to sell except in Alaska," Trinity wrote. The church is maintaining a careful distance—it's not saying it wants to decide, but it's saying Walmart's board ought to do so. Walmart tried to bury the proposal; the Security and Exchange Commission ruled in the company's favor. Trinity sued and won in federal district court, and now Walmart has appealed.