As you've likely heard by now, the Opposition has won the Malaysian election. To explain why that is such big news, I need to provide some context.
Prior to 1955, the Malaysian assembly had been hand-picked by the High Commissioner, who was chosen by Britain. The 1955 election was easily won by the Alliance, which was, as its name implies, an Alliance of parties; in particular, the Malayan Indian Congress, the Malayan Chinese Association, and the United Malays National Organization, or UMNO, which won 34 of the total of 52 seats in the Assembly.
The first post-independence election in 1959 saw the Alliance re-elected, winning 74 of the 104 seats
In 1963 the Malaysia we know today was formed, with the Peninsular areas being joined by Sabah and Sarawak, on Borneo, and Singapore. The Alliance quickly irritated the Peoples Action Party (PAP), the ruling party of Singapore, by reneging on a deal they had made to not contest seats there in local elections.
The 1964 election saw the Alliance win 89 of the 104 seats on the mainland. This, however, was a majority of the grand total of the 159 seats available. As a result of this overwhelming victory, Singapore withdrew from Malaysia the following year to become an independent country. The influence of PAP, however, would continue to be felt, as, PAP members in Malaysia would go on to create the Democratic Action Party, which would, more or less, be the main opposition party for decades to come.
The 1969 election was difficult for the Alliance. The Alliance managed to win 66 of the 103 seats on the Mainland; but this would fall short of a majority of the grand total of 144 seats. However, they managed to take 8 seats on Borneo, securing 74 of the 144 seats, and a Majority. They won only 44% of the vote, however, but, many seats had been won by acclimation.
By 1974, the Alliance had become Barisan National. This new alliance contained over half of the former opposition, including parties such as the Pan-Malaysian Islamic Party. BN won an overwhelming victory, taking 135 of the 154 seats. This would be followed by a similarly sized victory in 1978, winning 131 of 154 seats.
The 1982 election would see BN, lead by the new Prime Minister, Mahathir Mohamad. He would lead the BN to a victories taking 132 of 154 seats in 1982, and 148 of 177 in 1986.
Trouble began in 1988 when Mohamad was challenged for the leadership of UMNO, the main party in BN. In a close, and some say rigged vote, Mohamad emerged victorious, and began a purge of political opponents. Many of them would eventually start or join opposition parties. The purges eventually hit the judiciary with many judges being dismissed. The controversy caused the 1990 election to be comparatively competitive.
In 1990, BN won 127 of the 180 seats, a far lower share than in previous elections. Shortly thereafter, Anwar Ibrahim became Finance Minister and the economy took off like a rocket. By 1995, BN was able to win re-election taking 162 of the 192 seats. By 1998, Anwar Ibrahim had fallen out of favor with Mohamad and was arrested and charged with corruption and sodomy. This did not stop Mohamad from winning re-election in 1999 leading BN to taking 148 of the 193 seats. The main opposition was Barisan Alternatif (BA), a party Anwar Ibrahim had involvement with, which took 45 seats.
By the time of the 2004 elections, Mohamad had finally left the job of Prime Minister. BN won 198 of the 219 seats in elections that year. BA managed 24% of the vote, but only won 8 seats.
In time for the 2008 election, a large opposition alliance was formed known as Pakatan Rakyat (PKR). Joining BA were three other parties. the Pan-Malaysian Islamic Party, the Peoples Justice Party (with deep ties to Anwar Ibrahim), and the Democratic Action Party. Lead by Wan Azizah Wan Ismail, the first woman to lead a major political alliance in the country, PKR managed to take 48% of the vote and 82 seats, but still lost to BN, which took 140 seats on 51% of the vote.
The 2013 elections appeared to potentially be historic. Many were expecting PKR, now lead by Anwar Ibrahim, to win. In fact, when the results came in, PKR had taken 51% of the vote, compared to 47% for BN. However, due to the FPTP (First Past The Post) nature of the electoral system, BN still won a majority of seats, 133 compared to 89 for PKR.
This brings us to the current election
There is not much to say as most of the context is laid out above.
Anwar Ibrahim, whose earlier conviction had been overturned, had the overturning of that conviction overturned, and, as such, is back in jail.
In 2015 a major scandal hit the government related to 1MBD, a government run company. In short, the Prime Minister, Najib Tun Razak was accused of lining his pockets. Former Prime Minister Mahathir Mohamad returned to politics to demand Razak resign. In January of this year, Mohamad was named as the Prime Minister candidate for PH (Alliance of Hope) the successor to the PKR. His deputy would be Wan Azizah Wan Ismail, the wife of Anwar Ibrahim.
Polls for the election indicated that BN could likely still win a majority, thanks in part to a split in the vote between PH and the Pan-Malaysian Islamic Party, which would not be part of the opposition alliance.
Results, however, were decisive.
121 - PH - 50%
79 - BN - 36%
With a majority of the 222 seats won, PH has won a majority.
Mohamad has already been sworn in as Prime Minister, and Ibrahim has been pardoned. According to the plan of the party, he will take over as Prime Minister in two years. Outgoing PM, Razak, has accepted the loss. Despite this, all is not set in stone. Already, one party has withdrawn from PH. Current standings in Parliament are as follows.
113 - PH (majority)
79 - BN
18 - Islamists
12 - Others
By party, they are as follows (three largest shown)
55 - UMNO (BN)
47 - Peoples Justice Party (PH)
42 - Democratic Action Party (PH)
As with 2013, even despite the PH victory, there were accusations of gerrymandering to support BN. As someone who makes a regular habit of watching world elections, I see no evidence of this in most states. However, results from Perak have been unusual in the last few elections, including this one, that seems to have started with the 2009 crisis in that state.
There are also potential future roadblocks to keep an eye out for. The King of Malaysia is actually chosen by the various state/provincial Kings (sultans) as most states have their own King. The national King serves for 5 years, and can be re-"elected" down the road. Both Mohamad and Ibrahim have made enemies of the Sultan of Selangor, and should he become King of Malaysia, there could be potential issues.
Beyond that, this looks similar in some ways to the 1993 election in Japan, when members of various factions that broke off from the ruling party were able to unite and deal that party a democratic defeat. If what happens there will happen here, electoral reform may be in the cards.