What does it mean to "maintain" a plan under §1003?

[JWRB]

Hi everyone,

As the topic states, are there any definitions or cases that exemplify "maintaining" a plan?  The Advocate SC ruling that recently came down points to "funding and administering" as components, but I'm looking for something more concrete.

Based off of a plain reading, maintenance could easily fall on plan trustees (especially with a plan that's ceased funding), and I'm curious what you all think.

Thanks!