Abbas turns 80 on Thursday, with March 26, 1935 widely accepted as the date of his birth, although his entourage seems keen to avoid all mention of his advanced age and has no plans for any celebration.
On the same day, Netanyahu -- who last week ruled out the establishment of a Palestinian state if reelected -- begins consultations on forming his new government, a likely coalition of rightwing and religious parties.
The two men, who have traded mutual accusations over the collapse of the peace process, now look fated to deal with each other for several more years.
Born in the northern town of Safed in Galilee, in what is now Israel, this refugee has come a long way to reach a point where he holds all the keys of power within Palestinian society.
Abbas is responsible for any diplomatic contact with Israel. And as the Palestinians press their statehood campaign, it is he who has the final say in how it all plays out.
And for Netanyahu, who has four weeks to form a government, the day of reckoning is near, with the Palestinians planning to launch legal action against Israel as early as April 1, when they formally become members of the International Criminal Court.
- 'A real danger' -
Abbas also holds the keys to executive power, including the legislature given that the parliament, the Palestinian Legislative Council (PLC), has not met since 2007 when the Hamas forced Abbas's Fatah faction out of Gaza.
Although Hamas is his main political rival, its power base is in Gaza and it has hardly any presence in the West Bank where Fatah dominates.
"Abbas now has powers in his hands which he did not have before as a result of the divisions," said George Giacaman, a democracy expert at Birzeit University, referring to the Hamas-Fatah split.
Such divisions have left a "vacuum of responsibility" which has been largely filled by Abbas.
Not only is Abbas president of the Palestinian Authority, but he also heads the Palestine Liberation Organisation (PLO). And the strongest faction in the PLO is Fatah.
It is Abbas who will take the practical decision on whether to break off security cooperation with Israel and what steps the Palestinians will take against Israel at the ICC.
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He will also have to choose whether or not to resume some form of dialogue with Israel on ending the decades-long conflict.
"There is a real danger because everything is concentrated in the hands of one man who can decide everything," said Hassan Khreishe, deputy head of the Palestinian parliament.
Elected as PA president for a four-year term in January 2005, two months after Yasser Arafat's mysterious death, Abbas remains in power as there have been no new elections.
In April 2014, Hamas and Fatah agreed in principle to hold elections by the end of the year after trying to put an end to years of rivalry.
But the agreement has faltered, and the vote was never held.
- 'Totalitarian regime'? -
Under Palestinian Basic Law, the president can promulgate laws by decree if the PLC is not functioning.
But since 2007, Abbas has "promulgated more decrees than the PLC did in its entire 10-year existence," Giacaman said.
"This is not normal and it is very problematic."
The president has the right to sack the prime minister, meaning the current premier Rami Hamdallah owes his position entirely to Abbas -- because it has never been endorsed by parliament.
"Today we are moving towards a totalitarian regime run by Abbas," said Khreishe.
Abbas, he said, does not take anyone into account "and is not accountable" to any institution.
In the absence of a functioning parliament, the only legislative decision-making body is the PLO Central Council. But its policy decisions can only be activated by the PLO's Executive Council -- which answers to Abbas.
It was the Central Council which decided on March 5 to end security cooperation with Israel.
But, as usual, the final decision will rest with Abbas.