Apple's rejection of the Google Voice app for the iPhone went all the way to the top—the bad news was personally delivered to Google by none other than Apple's Senior VP of Worldwide Product Marketing, Phil Schiller.

New details of the controversial decision came to light today when the FCC released an unredacted version of Google's own confidential letter (PDF) to the agency. Google replied to a set of FCC questions about the Google Voice app rejection on August 21, but requested that the letter be kept private due to the "sensitive nature of commercial discussion." Interested parties immediately filed Freedom of Information Act requests to get at the juicy tidbits that might be found in such a letter; rather than fight the request, Google waived its confidentiality.

Most of the letter is routine, though the "confidential" section does describe Google's interactions with Apple (Google says it had no contact with AT&T throughout the process).

The Google Voice app was submitted to Apple on June 2, 2009. Between July 5 and July 28, Schiller had a set of meetings, phone calls, and e-mail exchanges with Google's Senior VP of Engineering & Research, Alan Eustace, about the app. Apple expressed one major concern: the "application duplicated the core dialer functionality of the iPhone," with the company telling Google it did not want any apps "that could potentially replace such functionality." On July 7, Schiller told Eustace by phone that the app was being denied for this reason.

This had been an issue earlier in the year, too, when Google tried to get its location-based social networking Google Latitude app approved for the iPhone. Apple didn't like Latitude because it might compete with the built-in Maps application and cause "user confusion," especially as the built-in app used Google Maps as its backend. On April 10, 2009, Schiller told Eustace that Latitude would be rejected.

The nature of the contact between Google and Apple on these apps shows just how high-level the process was and how important it was to Google. Apple's decision to eventually put the kibosh on both apps sounds plausible, if not "open" (never a real virtue of the iPhone and its App Store ecosystem), but it's still rather strange. We have reports from developers, for instance, that Schiller personally approved third-party Google Voice apps in April 2009.

Apple's own letter (PDF) to the FCC on this issue made clear that it had the same concerns about the third-party apps, which were pulled after initially being accepted. The odd part about Apple's response is that it insists that it never "rejected" the Google Voice app.

"Contrary to published reports, Apple has not rejected the Google Voice application, and continues to study it," said that letter. "The application has not been approved because, as submitted for review, it appears to alter the iPhone’s distinctive user experience by replacing the iPhone’s core mobile telephone functionality and Apple user interface with its own user interface for telephone calls, text messaging and voicemail."

This spawned plenty of developer skepticism—how was it possible to "replace" Apple's core functionality? Many people saw the sinister hand of AT&T behind the non-approval, especially since AT&T and Apple admitted that the wireless operator did indeed impose app restrictions (no VoIP over the data network, for instance).

Google's letter doesn't clear up the motives behind Apple's change of heart when it came to Google Voice apps, but it does remind us that this wasn't some issue handled by a denizen of the App Store approval process; this happened right at the top of both companies, and only after weeks of discussion.

Update: Apple has made one of its rare public comments, telling Ars that despite Google's account of the app rejection (a term Google uses repeatedly), "Apple has not rejected the Google Voice application and we continue to discuss it with Google.”