After months of sniping from the sidelines, Dr Mahathir Mohamad has decided to declare open war on Prime Minister Najib Abdul Razak.

A vitriolic salvo was unleashed on the eve of the sixth prime minister's sixth year in office.

This is the octogenarian's second bid to topple a serving prime minister, the first being successful, ironically with the current prime minister's support .

At that point, Mahathir believed that Najib was the best man to replace Abdullah Ahmad Badawi and the questions surrounding the murder of Altantuya Shaariibuu did not matter or warrant further investigation.

With Abdullah, speculation was rife then that Mahathir was livid with his handpicked successor for deviating from the script.

Abdullah was supposed to be a seat warmer but it was said that his Oxford-trained son-in-law and his band, known as the fourth-floor boys, had whispered grandiose ideas into his ear.

History repeating itself

The fifth prime minister, who earned notoriety for literally sleeping on the job and an agrarian at heart, was convinced to dismantle Mahathir's legacy and to carve his name in history.

Abdullah was bolstered by the fact that he led the ruling coalition to its biggest ever victory in the 2004 general election.

Mahathir was shunned, treated like an outcast and his views blacked out by the mainstream media, forcing the former premier to turn to alternative sources like Malaysiakini .

After the 2008 general election, which saw Abdullah leading BN to its hitherto worst-ever electoral debacle, Mahathir upped the ante.

In May that year, Mahathir, his wife Siti Hasmah Ali, son Mokhzani and party veteran Sanusi Junid quit Umno Baru, the party the former premier had founded in 1988.

He also urged other Umno members to do the same in order to pressure Abdullah to step down.

Mahathir’s decision had shocked Abdullah, who did not expect his predecessor to throw in the towel despite their differences.

Dr M promised to always be critical

On April 4, 2009, a day after Najib became prime minister, Mahathir rejoined Umno.

He handed his application form and the RM2 membership fee to Najib.

In thanking Mahathir for returning to Umno, Najib, who had no clue what the future had in store, remarked: “I believe Mahathir’s return will provide a strong impetus to Umno and can help in the rejuvenation of Umno and BN.”

And Mahathir when quizzed if he would remain critical of the Najib administration similar to his stance against Abdullah, replied: “I was critical whenever Umno went wrong.”

Now, the karmic wheel has turned and Najib finds himself in the position of Abdullah, who must be secretly enjoying the fireworks from a safe distance, and the mainstream media has once again toned down or censored Mahathir’s statements.

So would the former premier quit Umno for the second time to stamp his protest?