The first thing Debian would need to do, is to include a package for Qt 2.1 for users. Qt 2 is free software, thanks to the QPL meeting the definition of a free software license. Including both source and binaries of Qt would not violate the principles of the Debian project.
Once Qt becomes included in the Debian system, as a separate package, the GPL is no longer forbids including a binary package of KDE. I will go through the GPL section by section to "prove" it.
Section 1 of the GPL grants permission to redistribute verbatim copies of the source of KDE applications. Section 1 is very liberal, and I have heard no objections to KDE and Qt that derive from it.
Section 2 grants permission to distribute modified copies of the source of KDE applications. KDE would not need to be modified to work with Debian, since it uses systems like autoconf, automake, and libtool to ensure compatiblity across platforms.
Should, however, Debian need to make a change, Section 2 still grants the needed permission. KDE's dependence on Qt headers does not matter. Section 2 gives three conditions for distribution of modified versions, and then states immediately below:
These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program,
and can be reasonably considered independent and separate works in
themselves, then this License, and its terms, do not apply to those
sections when you distribute them as separate works. But when you
distribute the same sections as part of a whole which is a work based
on the Program, the distribution of the whole must be on the terms of
this License, whose permissions for other licensees extend to the
entire whole, and thus to each and every part regardless of who wrote it.
Qt is clearly a work that is identifiably separate from KDE. It Qt and KDE are distributed as separate packages, then that classifies them as "separate works." Therefore, the requirements in section 2 do not apply to Qt, if KDE were to be modified. There would be no conflicts.
Section 3 grants permission to distribute compiled versions of the KDE applications. Debian argues that since KDE links in Qt, KDE is illegal to distribute in binary form, since Section 3, part b would be violated:
b) Accompany it with a written offer, valid for at least three
years, to give any third party, for a charge no more than your
cost of physically performing source distribution, a complete
machine-readable copy of the corresponding source code, to be
distributed under the terms of Sections 1 and 2 above on a medium
customarily used for software interchange; or,
Qt's source cannot be distributed according to the terms of Sections 1 and 2, since the QPL does not grant all the freedoms of Section 2. However, this is not the first time that a GPL application has been linked to a non-free library. Consider all the times that GPL apps have been linked to non-free C libraries, often used on non-free operating systems. The GPL takes these situations into account, in section 3:
The source code for a work means the preferred form of the work for
making modifications to it. For an executable work, complete source
code means all the source code for all modules it contains, plus any
associated interface definition files, plus the scripts used to
control compilation and installation of the executable. However, as a
special exception, the source code distributed need not include
anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the
operating system on which the executable runs, unless that component
itself accompanies the executable.
If the latest versions of Red Hat, SuSE, Slackware, Caldera, Corel, and Mandrake all include Qt, then I would assert that the overwhelming majority of Linux systems are being distributed with Qt. And, if Debian decided to include Qt, then that would mean that probably over 95% of copies of Linux shipped with Qt. How can that not qualify as being "normally distributed... with the major components... of the operating system"?
Sections 4 and 5 seem to be the only parts of the GPL, as applied to KDE, that the Debian developers want to exercise. These sections state the conditions under which the software may not be redistributed, and that one is not obliged to accept the rights the license does grant.
Sections 6 and 7 are complicated, and irrelevant to this discussion.
Section 8 could apply to KDE, should KDE wish it:
8. If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
those countries, so that distribution is permitted only in or among
countries not thus excluded. In such case, this License incorporates
the limitation as if written in the body of this License.
However, it is the opinion of some KDE developers (I dare not claim to speak for all KDE developers; that would be silly and untrue) that the distribution of KDE is not restricted by the use of the Qt programming interface, since Qt is free software. Therefore, no restrictions have been added. Debian can't be bound by a restriction that hasn't been added.
Section 9 states that revisions of the GPL, with new version numbers, may be released.
Section 10 is what is being exercised by Günter Bechly. Section 10 tells one to ask the copyright holder, if one wishes to distribute the software under a different license.
And, finally, Sections 11 and 12 disavow any warranty on the software.
So, I am forced to conclude that the 12 sections of the GPL do grant Debian permission to distribute both source and binary packages of KDE.
I now submit this to the kuro5hin.org community, and the free software community at large, because I feel that the KDE side of this dispute is often overlooked.