It will be months before a verdict is reached in the corruption case brought against ex-Malaysian Prime Minister Najib Razak, who is accused of siphoning money from a former unit of the state-owned 1MDB development fund. (He has pleaded not guilty to the charges.) But his arrest this week is more significant than many people outside the region may realize. It’s the first sign of something that modern Southeast Asia has till now lacked - accountability for the region’s top leaders.

Since gaining independence after World War II, former colonies in the region have struggled to develop political systems that could accommodate indigenous power structures. More often than not, local elites simply imported and modified the political systems of their European overlords. Thus, former British colonies Singapore and Malaysia adopted the Westminster system, while the Philippines took on the American system. Indonesia and Thailand embraced the worst aspects of both and have suffered politically ever since. (In Brunei, an absolute monarchy with aspects of the Westminster system, the last word always belongs to the Sultan.)

These political systems mostly codified existing hierarchies. Those at the top preserved their privileges and their immunity from the law. If there’s one thing Southeast Asian elites understand, it’s that the higher you are in the political food chain, the greater your ability to act with impunity.

Till today, for instance, not a single top political leader has been found accountable in a court of law for the hundreds of thousands of people massacred in Indonesia’s anti-communist purges in the mid-1960s, the shooting of students in Thailand in the 1970s, the genocide in Cambodia from 1975-’79, and killings during the martial-law era in the Philippines.

The record for corruption is even worse. Former dictators Suharto in Indonesia and Ferdinand Marcos in the Philippines are widely acknowledged to have stolen billions while in office. Yet, while both were eventually forced from power, neither was ever charged for any crimes. In fact, both Suharto and Marcos are officially buried in their nations’ heroes’ cemeteries.

Marcos’s eldest son, Ferdinand “Bongbong” Marcos Jr., could well become the next Filipino president; he lost the 2015 race for vice-president by less than one percent of the vote. In Indonesia, the man who came in second to President Joko Widodo in the 2014 election was Prabowo Subianto, Suharto’s son-in-law and a special-forces general accused of human-rights violations in East Timor in the 1990s. He, too, has a decent chance of winning the next election.

Najib fits the mould perfectly. As the son of Tun Abdul Razak, Malaysia’s second prime minister, he was literally born to rule. He became chief minister of the state of Pahang at the tender age of 26 and prime minister in 2009 at the age of 56. In other words, he’s never had a job outside politics. And, in his entire political career, he’s always held leadership positions. If anyone could be considered untouchable in the Malaysian political system, Najib was.

Of course, it’s ironic that Prime Minister Mahathir Mohamad is the man to bring Najib down. Mahathir, who virtually invented strongman rule in Malaysia, hardly challenged the culture of impunity during his first stint as prime minister between 1981 and 2003. During that time, massive financial scandals broke out in both, government-owned Bank Bumiputera and the central bank. (Mahathir was never personally implicated in either, but they did occur on his watch.) Going after Najib now is politically convenient, given public anger over alleged corruption and graft at 1MDB.

Whatever the motivation, though, Mahathir has now set a precedent. The young populations of Southeast Asia can see that they have the right to scrutinize their topmost leaders. With luck, that will inspire them to build up a press and civil society that can hold those leaders accountable, to strengthen the independence of their judiciaries or, at least, to vote in politicians who will.

Mahathir himself is a brand name among Southeast Asians, widely acknowledged as the region’s most senior statesman; how he handles the Najib case will be a cue for others in the region. For example, a cartoon published in a Thai newspaper shows two men looking to chop down the thick roots of “corruption.” The left panel shows a discouraged man meant to symbolize Thai Prime Minister Prayuth Chan-o-cha, whose tiny axe is barely making a dent. The man on the right - labelled a “92-year-old Malaysian” - is hacking great gouges out of the tree. The Jakarta Post recently published an article citing the need to fight corruption as a key lesson to learn from Mahathir’s electoral win.

Activists and international organizations such as the World Bank and Asian Development Bank have sought for decades to improve governance across Southeast Asia, with mixed results. If conducted fairly and transparently, Najib’s trial may give that effort just the push it needs. - Bloomberg