strident Roman Catholic admits that it was once possible for priests to ordain priests. There are a number of ancient references to this (from the early church) and there exists documentation from the medieval period of priests ordaining priests. In 1400, for example, Pope Boniface I gave permission to the Abbot of S. Osith in Essex to ordain to the priesthood. Though this permission was revoked in 1403, the validity of their orders was not questioned. Today, however, the Church affirms that only bishops ordain priests. The Lutheran problem, therefore, lies not in the form (priestly ordination) nor in the lack of apostolic succession but in the lack of papal permission. So to declare Lutheran orders (priestly ordination) would not require adding apostolic hands or the action of a bishop but simply the recognition of those orders from the Pope.
I write this not because I or anyone I know is seeking such recognition or needs it, for that matter. Instead, I write this because the usual arguments against the validity of Lutheran orders may not here apply and that the irregularity of those orders (from Rome's perspective) could rather easily be resolved if Rome so chose to resolve this issue. Priestly ordination may have been an irregularity in history but it is not unknown and, in some cases, proceeded with the dispensation of the pope.
Again, Lutherans are not necessarily interested in nor are they seeking papal recognition but it is one of many impediments cited as a roadblock to the ecumenical task. Lutheran orders are obviously not in question from the Lutheran side of the ecumenical equation but they have been from the Roman side. It may be a problem but it is certainly an easily resolvable one. Recognition from the Pope gives credibility and validity to the orders recognized. It must be recalled that Lutherans did not seek priestly ordination until there was a lack of bishops to ordain candidates to serve the Lutheran parishes. At that point the Lutherans returned to an ancient, if somewhat unusual, option. The option was not unknown nor without precedent though we all agree it was without papal permission.
Something to think about. . .