A truth once understood but now seemingly forgotten

Bishops, not cardinals, are essential to the constitution of the Church. By ecclesiastical (not divine) law, the cardinals are the electors of the pope. But it would not be contrary to her essential constitution for the Church to be left without cardinals. Saint Robert Bellarmine taught that if this should happen, the right of electing the pope “would pertain to the neighboring bishops and the Roman clergy, but with some dependence on a general council of bishops.” 

Thus we encounter, again, the problem of jurisdiction. Though a pope can give non-diocesan bishops the right to participate in a general council, as Pius IX did at the Vatican Council, it is true that only bishops with ordinary jurisdiction are entitled to participate by divine right (as opposed to by ecclesiastical law or custom).

Now the question must be asked: is it more logical to believe that it is possible for there not to be any bishops with ordinary jurisdiction in the Church today and thus that there must be cardinals, otherwise there would be no papal electors? Or that it is possible for there not to be any cardinals and thus that there must be bishops, or at least one bishop, with ordinary jurisdiction?

Of course, other questions must be asked. Who are those bishops? What of the Roman clergy?