Perhaps the government was looking back nervously to the first Bersih march, in 2007.

ECONOMIST: An overzealous government response to an opposition rally

Ms Ambiga is co-leader of the Bersih movement, a coalition of NGOs campaigning for free and fair elections.

ECONOMIST: Politics in Malaysia

She points out that her Malay co-leader of Bersih, a famous writer called A. Samad Said, has never been targeted.

ECONOMIST: Politics in Malaysia

Several leaders of Bersih, including Ambiga Sreenivasan and Maria Chin Abdullah, were among the 1, 401 people that police said were arrested.

BBC: Malaysia: Police fire tear gas at banned rally

Over the last few years, Mr. Najib bowed to demands from the civil society group Bersih for tighter controls and monitoring.

WSJ: Review & Outlook: Malaysia's Road to Democracy

Similarly, in Malaysia, the government has at times seemed more worried by Bersih, a campaign for electoral reform led by Ambiga Sreenevasan, a lawyer, than by the formal opposition.

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Meanwhile, Ms Ambiga and other Bersih co-leaders (not the Malay one) have been issued with a bewildering demand for compensation from the Kuala Lumpur city council for costs incurred during the April rally.

ECONOMIST: Politics in Malaysia

The current prime minister, Najib Razak, deputy prime minister in 2007 before taking over the top job in an internal party coup, must have feared that the second Bersih rally might be a similar portent.

ECONOMIST: An overzealous government response to an opposition rally

Opposition politicians were quick to join Bersih.

ECONOMIST: An overzealous government response to an opposition rally