The previous talk [Godmar Back's] was about how the red line is a useful system-structuring abstraction; [it helps us understand which parts of the system need to maintain which properties for the whole system to be secure]. This talk will be about how the red line shouldn't [have to] appear in a running system implementation.

Partial evaluation is an idea that is making interesting progress in the languages community, but is stuck above the red line because, well, it's in the languages community. Partial evaluation is a nice model that lets us have specialization (for performance) and extensibility, too.