I'm not sure these two cases tell us much about whether it's smart/right/appropriate for Democrats to discuss their faith. The first is really about race, not religion. Wright's comments would have become an issue if Obama never once mentioned his Christianity and if Wright was someone Obama worked with closely as a community organizer instead of his pastor.
The second example is tougher only because of how Clinton has chosen to respond to the Wright story. There is a strong case to be made that people choose their religious communities based on spiritual factors, not political ones. Most individuals have plenty of outlets for their political interests. They don't need their church or temple or small group to be yet another place where they discuss policy and politics.
(More after the jump...)