Let's hope for the newbies sake, that's the worse case scenario. I've spoken with a higher-up (before today's announcement), that 1) they would not use the "F" word to newhires just for the sake of it, gotta be WWIII or something huge (oil at 110 doesn't quite cut it), 2) They are very reluctant to stop the whole hiring process, because it would take them months just to get the pipeline filled again. 3) They will not CX flights because of short staffing during peak summer months, unlike AA or NW or UA.
Granted, they may choose to continue at a slower pace, and put people in a pool. I think the next few classes are safe, because those new hires will be flying the peak summer months when they get off training. The late summer classes may be anybody's guesses, but I doubt they'll stop all classes altogether. We still have few new a/c hitting the property, and they need to be manned.
One thing needs to be mentioned is that, the transition of domestic flying to the int'l side has been the plan all along, since all of our a/c are int'l capable, i.e. MD-88 will fly from ATL->CUN. So it may seem a significant reduce flying for other airlines, it probably not such a big hit in staffing for DAL.