Veteran newsman Kadir Jasin said he believes that former prime minister Mahathir's Mohamad's second exit from the party is a debilitating blow to Umno.
"Mahathir quitting is a kick to the groin of Umno," he said in a blog post today.
While he said that it is still too early to say how many Umno members will follow in the ex-PM footsteps, Kadir posited Mahathir quitting was enough to demoralise party members.
Umno is in the midst of unrest as party members speak out over the 1MDB and RM2.6 billion 'donation' scandals involving the president.
Najib has started a purge that has seen ministers, menteri besar and grassroots members either being expelled or suspended for going against him.
Kadir said that Mahathir's leaving Umno may be for the best as it would save the former PM from having to endure invective and verbal lambasts from Najib loyalists.
"It will also make it easier for him to be the torch for all citizens who want to save Malaysia from Najib's perceived indulgences," he said.
Mahathir, rebels within Umno, opposition leaders and civil society activists have called for a coalition that crosses traditional partisan boundaries to work towards holding Najib to account and asking him to step down or remove him from power.
Kadir wrote that he himself had left Umno in June last year as he no longer believed he could contribute to the party as he was no longer in line with the current party leadership.
'True Machiavellian'
Umno supreme council member Rahman Dahlan however tweeted that the Malay party would survive all efforts to destabilise it.
"As a party with more than three million members and entrenched organisation, Umno will survive any attempt to destabilize it including resignations.
"Many Umno members cried when Tun abruptly resigned as PM in 2002. But this time around, tears no more," read his tweet.
While fellow Umno supreme council member Annuar Musa in a statement labelled Mahathir's resignation as an attempt to weaken the party and kill it, claiming that this was the hallmark of Mahathir whom he labelled as a 'true Machiavellian'.
Annuar said that Mahathir was willing to destroy Umno and hand the country over to the opposition on a platter just to spite the Umno president.
Annuar blamed Mahathir for handing over Kelantan, Selangor and Penang to the opposition in 2008 when he left the party the first time. However Annuar said that he was certain Umno would persevere and not be threatened by the actions of one man.
Mahathir had left Umno in protest before in 2008 over what he claimed was the bad leadership of former premier Abdullah Ahmad Badawi. He rejoined the party after Abdullah stepped down the following year to be replaced by Najib.
