

Precedents in Papal Election History and Law
In 1059 Pope Nicholas II limited the election of the Pope to the Cardinal Bishops, that is the six or seven Bishops of the Suburbicarian Sees surrounding Rome.
5. But in the wickedness of depraved and iniquitous men shall so prevail that a pure, genuine, and free election cannot be held in this city, the cardinal bishops with the clergy, and a few laymen shall have the right to elect the pontiff which they deem most fitting. (Note the Cardinals having all died or defected prior to 1990, a few layman proceeded to elect.)
6. But if after and election any disturbance of war or any malicious attempt of men shall prevail so that he who is elected cannot be enthroned according to custom in the papal chair, the pope elected shall nevertheless exercise the right of ruling the holy Roman church, and of disposing of all its revenues, as we know St. Gregory did before his consecration.
In 1179 the Third Lateran Council decreed with the approval of the Pope that it shall require two thirds to elect the Pope. We decree, therefore, that if by chance any hostile person has sown cockle among the cardinals to influence the election and if a complete agreement cannot be reached, two-thirds agreeing while the other third is unwilling to agree or arrogate the right to choose another, he without any exception shall be acknowledged as pontiff of the universal Church who has received two-thirds of the votes. ... But in the Roman Church there is constituted something special, because recourse cannot be had to a superior.
Pope Clement IV died November 29, 1268 at Viterbo. The Papacy remained vacant for two years, nine months and two days. Prior to this time, the Papal Election was held in a chapel in a palace or other convenient place. However, the Cardinals failed to produce a Pope. The laity of Viterbo intervened and first boarded up the doors and windows and placed the Cardinals on bread and water. When even this could not induce them to elect, they proceeded further. One of them proposed to authorize six cardinals to name the pope, all promising to recognize the one thus named by compromise. It was necessary to have recourse to such an expedient, for the conclave had lasted three years. Ramieri Gatti, captain of the city, had already had the roof uncovered so that the inclemency of weather might dispose the cardinals to make a final choice. (De Montor's Lives of the Roman Pontiffs, volume 4, page 168) September 1, 1271, the second longest interregnum in Church history ended. It was the intervention of the laity to force the Cardinals to complete their solemn task that ended this interregnum.
In 1274 the Second Council of Lyons provided with the approval of the Pope for reformation of the Papal Election Law:
Canon 2: Where a greater danger exists, there without doubt a fuller deliberation is necessary. How grave are the losses resulting from a prolonged vacancy, and how full of dangers it is to the Roman Church, is shown by prudent consideration of the past. ... With the approval of the holy council, therefore, we decree that when the pope dies in the city in which he resided with his curia, the cardinals who are present in that city must wait only ten days for their absent colleagues. (Note: the vacancy beginning on October 9, 1958 shows just how grave a danger a prolonged vacancy is!)
But because the faithful should not so much put trust in a search for a pope as hope in the moving force of humble and devout prayer, we add to this decree that in all cities and in other prominent places, when word is first received of the certainty of the pontiff’s death, the solemn obsequies having been celebrated for him by the clergy and laity, every day till it is known for certain that a head of the Church has been elected, prayers be offered to God, beseeching Him that He who brings about harmony in His realms, may so move the hearts of the cardinals toward an agreement in the election that a speedy, harmonious and suitable choice, that will promote the salvation of souls and answer the needs of the whole world, will result from their unanimity. (Note, the sede vacantists err gravely in not continuing this prayer!)

The precedent of first in time, first in right has always held, despite the confusions, especially of the Western Schism. Pope Innocent II was first in time opposed to Antipope Anacletus II, who was elected by the majority of the Cardinals. The small number did not prevent (Saint) Bernard from leaving his monastery to defend the validity of Innocent's claim. History has ALWAYS held Innocent to be Pope. It has been declared that the first elected in the Western Schism, Pope Urban VI and his successor were the true Popes.
The only exception to first in time first in right is the attempted promotion of a schismatic, heretic or apostate to the Papacy, as declared in the infallible Bull Cum Ex Apostolatus Officio. Cum Ex permits us to appeal to the secular authority to aid us in riding ourselves of an heretical usurper. If we can make such an appeal, can we not proceed to fill the vacancy ourselves. The Church consists of all who are baptized and profess the Faith, whole and entire without any exception.
Michael Fighting
"Michael…who standeth for…thy people," — Dan. 12:1-12