Yes, it is a condition, insofar as it is a condition for divorce, which is a condition for petitioning for an annulment.
In other words, it looks like the (US) Church reasoning is: Don’t approach for annulment unless you’ve tried everything to make the marriage work, the proof of the impossibility of which is your divorce.
But the reasoning seems flawed in two ways:
A couple could be going along just fine and their “marriage” could still be invalid (does it not really matter to the Church as long as everything’s “stable”? In the case of psychological incompetence, e.g., PDs, one spouse/parent could be going under as they are keeping things appearing “stable”);
Divorce, especially in a culture of no-fault divorce, doesn’t prove anything about how “hopeless” the situation is. People could just be in a rush to split, gotten their divorce, and now are here to waste the Church’s time to ease their consciences. (On this last point, does anyone know of anyone who got divorced and then the Church said, “Mmmm no, you’re married, still”?)
And this is all on top of the problem of “What does what we’re doing now have to do with what was (or wasn’t) the case then.” In other words, we might be getting along great right now, we might be at each others’ throats now, we might be somewhere in between, but that doesn’t change that we’re not actually married. In my original post I suggested that the Church’s response to this might be: Well, if you tried to reconcile before your divorce, maybe you’ll be open to making it work and getting married after the annulment (for the first time). In other words, from hope to no hope to hope because…we weren’t married?
To everybody: Please let’s not talk about un-real cases in which a couple is there before the tribunal, getting along fine, but have detected something that may mean they’re (objectively) not in good standing with the Church. That’s not why a person (or persons) in a couple approach a tribunal (they approach a priest in that case). You go before the court because you feel something is deeply wrong. As in so bad they think your house may be built on sand. Indeed, the (US) Church’s own “no hope of reconciliation” (i.e., divorce) threshold presumes such a state of emergency.