Not long after midnight, the crowd of thousands began to sense that something historic was taking place. They had gathered on a vast lawn to watch the election results roll in through the night, and the mood was cheerful and relaxed. Here, in Petaling Jaya, a heavily residential city that blends into Kuala Lumpur, support for the opposition party, Pakatan Harapan, the Alliance of Hope, runs high, and as P.H.’s tally began to outstrip that of Barisan Nasional, the ruling party, everyone present began to contemplate the unthinkable: the end of the only government Malaysia has ever known. The ramifications of P.H.’s stunning victory in Wednesday’s elections are only just starting to filter through. The person who appears to be our new prime minister is Mahathir Mohamad, who is 92 years old and earlier served as prime minister — with B.N. Even after the election commission confirmed this morning that P.H. had won at least 112 of the 222 seats in Parliament (or the simple majority that entitles it to form the next government) Najib Razak, the outgoing prime minister, was not clearly conceding his loss. Twelve of the country’s 13 states also held assembly elections yesterday, and B.N. won in just three.