The NMB doesn't decide to "release" you to strike or not. If they issue a proffer of arbitration (what the union is asking for) and then either side declines to enter arbitration you go to a 30 day cooling off and then you are released to strike.

SO - The NMB offers to arbitrate, if you decline the off then you do 30 days then you are released to "self help". Once you decline the proffer the NMB can't do anything to stop you from striking.

Stoping a srike after the 30 day:

Durring the 30 day cooling off, the NMB will evalute a strike and inform the President, if the President wishes to advert a strike he will create a Presdiential Eval Bord. PEB usually has 30 days to develop a proposed agreement and present that agreement to the parties for consideration. After the PEB delivers its proposed agreement, there is a further 30-day cooling off period.

If the parties reject the PED agreement then they are relased to self-help after the seccond 30 day period.

The only way to stop a strike after this is done for Congress to mandate an agreement it with legislation.

SO if the NMB offers to mediate (issues a proffer of arbitration) the union can take it all the way to a strike unless in the end congress says no.

We all need to know how our CBA process works...