The opposition in the small West African country, however, fears Jammeh will use a judicial system.
The opposition in the small West African country, however, fears Jammeh will use a judicial system -- considered by experts to lack independence -- to give legitimacy to his attempt to hang on to power.
The legal complaint
The ruling Alliance for Patriotic Reorientation and Construction (APRC) filed a complaint with the Supreme Court on December 13 alleging that opposition leader Adama Barrow was "not duly elected or returned as president, and that the said election was void".
The court challenge came after Jammeh had surprised observers by conceding defeat after 22 years in power on television, before changing his mind.
It said the country's Independent Electoral Commission (IEC) had violated electoral law, announced a December 5 recount without the consent of the APRC, and that its returning officers intimidated legitimate voters and turned them away on election day.
The Supreme Court
The Gambia's Supreme Court has lain dormant since May 2015 with Chief Justice Emmanuel Fagbenle, a Nigerian, the only current sitting judge.
Judicial independence is "the exception rather than the rule," said Niklas Hultin, an assistant professor at the US's George Mason University and Africa specialist.
"Where the Supreme Court and other high-level courts have asserted their independence, there has usually been some kind of retribution on the part of the executive," he added.
Jammeh fired several judges last year after they commuted the death sentences of former military officers to life imprisonment.
Jammeh needs to appoint four more Supreme Court judges for the constitutionally required panel of five to hear the challenge, and six if the decision requires a judicial review.
Complicating matters, the target of his complaint, the Independent Electoral Commission, is represented by Jammeh's own Attorney-General.
The Gambia's most influential lawyers' group, the Bar Association, has described any future hearing as therefore "fundamentally tainted".
A Bar Association statement said the challenge was "tantamount to one being a judge in his own cause considering that the outgoing president has already pre-empted the outcome of court process by declaring the election result as a nullity".
President-elect Barrow says Jammeh has left cases against the government to stack up by failing to appoint justices.
"There are a pile of cases that are waiting... but he doesn't care about it," Barrow told AFP. "And now he has a case, if he appoints judges we will see this is personal interest, and not in the interests of justice."
Senegalese political analyst Babacar Justin Ndiaye believes Jammeh's aim is to obtain better terms for his exit, given the universal condemnation of his volte-face and lack of other options.
"It's a strategy of giving him time, making the situation worse, wearing down the international community and finally to look for some sort of compromise, an arrangement," he told AFP.
Jammeh has "played his cards well", Ndiaye said, leveraging his continued support from important sections of the military to keep the Gambian population from taking to the streets against him.
If Jammeh wins the case at some point in the future, new elections could be called with a President Barrow in State House. That would be a "unprecedented" situation in Africa, according to Ndiaye.
The United States has said it does "not believe (the case) will be heard by a credible court dedicated to ensuring the integrity of The Gambia's democratic process", a reaction that was notably more hardline than the UN and regional bloc ECOWAS.
"It is OK for the legal process to be going on," the UN's west Africa envoy Mohamed Ibn Chambas told AFP Wednesday. "That legal process has nothing to do with the term of his mandate," he added.
Banjul-based diplomats have emphasised that the most important focus now is the handover of power still expected on January 19, rather than the outcome of the legal case that for now remains looming in the background.