Andy Greenberg writing for Forbes:
In its motion, Twitter offers three arguments against turning over that data: First, that the data belongs to Harris under Twitter's terms of service, and handing it over would violate both those terms of service and the SCA. Second, it argues that handing over Harris's data would violate the Fourth Amendment's protections against searches without a warrant, which it argues applies even when the government is seeking information about allegedly public activities like a user's tweets. And third, it points out that Twitter is in California, and argues that the New York prosecutors need to make their case to a California court to obtain Twitter's data.
Way to go Twitter!
Also: the motion.