The network neutrality debate has taken another turn with Robert Quinn, AT&T’s VP on federal regulatory issues, telling FCC Commissioner Robert McDowell that, “use of a P2P file-sharing application would constitute a material breach of contract for which the user’s service could be terminated.” In a letter (pdf) he sent to McDowell in response to questions, Quinn quickly added that the carrier hasn’t kicked anyone off its wireless network yet for using P2P. It’s assumed McDowell will use AT&T’s statement to argue against a proposed order from the FCC that will punish Comcast (NSDQ: CMCSA) for allocating less bandwidth to certain content while not being clear about its rules in small print. The order is still expected to pass tomorrow with support from FCC Chairman Kevin Martin and both Democrats that currently hold seats at the FCC. Following Quinn’s letter, questions abound as to whether AT&T’s stance might affect the use of popular applications for the iPhone such as Pandora that clearly fall into the P2P category.