OK, I reread the article, not a lot of info there, but I'll take a stab at how I think this is working.
First, my single-employer pension (different rules) is insured by PBGC. MegaCorp and I have/are paid/paying into the insurance fund. My pension is guaranteed, but there is a cap on the amount (and no COLA). If my company cannot fund my pension, PBGC is there (hopefully) to fill in the difference between what MegaCorp can pay and my pension - up to the cap.
So, if my pension exceeded the cap (it doesn't), and MegaCorp went belly up, I could be in a news article saying my pension was cut.
What I think is happening here is, the PBGC guarantees for these multi-employer plans may be low relative to the pensions, and there may be COLA involved (my pension, or any PBGC payments are non-COLA). So they are cutting what is being paid from the corp fund, in order to stretch it out, so they don't run out of funds. If they run out, the pensioners would fall all the way down to the PBGC caps.
This is mostly guesswork on my part, but I have a feeling that's close. In made-up numbers, say a pensioner is now getting $70K, and PBGC cap is $35K. If they keep paying $70K, they run out in X years, and the pensioner is down to $35K. But if they cut to $50K now, they can hold out longer, maybe indefinitely, before they have to turn it over to the PBGC and the pensioners get cut to $35K.
So this law allows them to make that stretch cut, before just running out. And members need to approve it, so they can decide if that is in their best interests. But I would not be surprised if some hold out, hoping for some other form of relief.
I hope someone can confirm/deny this.
-ERD50