> If I have the rights to re-license software, and I re-license the > software, why do I not have permission to enforce these rights?
Because you have the permission to re-DISTRIBUTE (not "re-LICENSE") the software and nothing else. In case of GCC, you have the explicit permission to relicense the work under a later version of the GPL. In the case of the GNU Lesser GPL, you have explicit permission to relicense the work under the GPL. So depending on the license, you might have permission to relicense the work.