1. Agreements made in times of plenty (call it: T1) can be sustained only if plentifulness is sustained in a later time (T2).2. Currently (the later time, T2), plentifulness is unsustained.So 3. Agreements made in times of plenty (T1) cannot be sustained currently (T2).4. Social safety net agreements (public pensions, social security, and medicare payouts) were made in T1.So 5. Social safety net agreements cannot be sustained in T2.
So, 1 and 2 are questionable premises, I think. But perhaps defensible. The more interesting argument, though, relies upon 1 and 2 to prove something that would ruffle the feathers of those who usually make the above argument.
6. An agreement to reduce the tax burdens for the top percentile of wage earners was made during T1.7. A reduction in the tax burden for the top percentile of wage earners cannot be sustained in T2.
Such a substitution as in (6) is either a reductio against the Conservative position, or it serves to reveal just how wrongheaded is (1). That is, in order to circumvent (6), one might want to argue that, of course all agreements made in t1, when we were flush with cash, cannot be sustained at t2, when we weren't, but that doesn't mean that some of them cannot be - indeed, that some of them must be. But if so, then we're in a debate about which t1 agreements are appropriate to maintain in t2 crises, and it is no longer obviously the case that we ought not to maintain the safety net.
Indeed, the debate shifts to a question of what (1) really justifies. I'd argue that it justifies making agreements in times of plenty that are made because times are plentiful - that is, agreement we could not make in times of distress. And if that's right, we should ask ourselves: which agreements would we make in times of plenty that we would not make in times of distress?
Safety Net: Would we agree to maintain a social safety net in times of plenty, but not in times of distress?Tax Cuts: Would we agree to tax cuts in a time of plenty, but not in times of distress?
Now, there are so-called economic arguments for each of these positions, and no doubt, the questions are not quite as finely-tuned as they might be. But even so, my intuition is that it is more obvious that tax cuts oughtn't be made in times of distress than that a safety net oughtn't be maintained in similar times. And perhaps one motivation for this intuition is that a safety net is meant for times of distress; indeed, if there never were times of distress, there would never be a safety net - no safety would be required, because there would never be any danger. The intuition in favor of tax cuts, however, does not seem, to me, obviously motivated in quite the same way.