Twenty-second Amendment to the United States Constitution
As worded, the primary focus of the 22nd Amendment is on limiting individuals twice elected to the presidency from being elected again. Due to this, several issues could be raised regarding the amendment's meaning and application, especially in relation to the 12th Amendment, ratified in 1804, which states, "But no person constitutionally ineligible to the office of President shall be eligible to that of Vice-President of the United States". While it is clear that under the 12th Amendment the original constitutional qualifications of age, citizenship, and residency apply to both the president and vice president, it is unclear whether someone who is ineligible to be elected president could be elected vice president. Because of this apparent ambiguity, there may be a loophole in the 22nd Amendment whereby a two-term former-president could be elected vice president and then succeed to the presidency as a result of the incumbent's death, resignation, or removal from office (or even succeed to the presidency from some other stated office in the presidential line of succession).
Joseph Estrada
Joseph Estrada stated in interviews that he would be willing to run for the opposition in the event that they are unable to unite behind a single candidate. Fr. Joaquin Bernas and Christian Monsod, members of the constitutional commission that drafted the 1987 Constitution, stated that the constitution clearly prohibits any elected president from seeking a second term at any point in time. Romulo Macalintal, election counsel of President Arroyo, clarified that the constitutional ban doesn't prevent Estrada from attaining the presidency in the event that he were to be elevated from the vice-presidency, for example.
However, Rufus Rodriquez, one of Estrada's lawyers, claims that the former president is within his rights to do so because the prohibition banning re-election only applies to the incumbent president.