Our church does a Sunday collection. Half of each month's proceeds are donated to an outside nonprofit organization selected by a church committee each month. I'm presuming the contributions, which I make out to the church, are fully tax deductible. What if the nonprofit organization that receives half of the offering is a 501(c)(4) instead of 501(c)(3)? What if the congregants know in advance what group the church will be supporting and decide to give more because they know a worthy cause will benefit?
As long as the church (or any other 501(c)(3) charity) is making the decision and retains ultimate authority over its split of the collection each month, your gift should be deductible. It would not be deductible if you earmarked your gift for a (c)(4) social welfare organization.
The church has to operate “exclusively,” i.e. “primarily,” for religious purposes or it could jeopardize its exemption. But an occasional gift from an active church to a (c)(4) organization, even if not for a charitable purpose, is unlikely to cost its exemption.