Russia's influence is at risk in the Southern African nation of Angola as voters head to the polls

Russia's long-held ties with the Southern African nation of Angola could be in jeopardy as the Moscow-friendly government faces its toughest electoral test in decades.

The ruling leftist MPLA (People's Movement for the Liberation of Angola) has been in power for nearly five decades since securing the oil-rich nation's independence from Portugal in 1975. 

On Wednesday, however, the party faces what analysts believe to be its tightest election yet, as opposition parties – principally one-time rebel movement UNITA (National Union for the Total Independence of Angola) – capitalize on widespread discontent fueled by high levels of poverty and unemployment.

This year is the 20th anniversary of the end of the Angolan civil war, which raged for 27 years until original UNITA leader Jonas Savimbi was killed in action. 

However, the country's control over its vast reserves of oil and minerals has not brought the widespread prosperity that many of its population had hoped for in the two decades of peace that followed, and many in rural areas have felt increasingly left behind.

The ripples of Cold War history and proxy politics are deeply entrenched in Angola, one of the largest economies in sub-Saharan Africa and its second-largest oil producer.

"UNITA was the 2nd largest recipient of U.S. covert aid during the Cold War, after the Afghan Mujahideen. That ended in 1993, but UNITA maintained its pro Western stance," said Alex Vines, head of the Africa Programme at Chatham House.

Meanwhile, the MPLA was a Cold War proxy for Moscow and has maintained close ties with the Kremlin throughout its tenure. 

Under current President Joao Lourenco, who succeeded 38-year predecessor Jose Eduardo dos Santos in 2017, the MPLA has diversified its foreign affairs and opened the country up to the West.

Vines noted that while Russia is important for defense and diamond mining – with mining group Alrosa maintaining a strong presence in Angola – China's influence is much deeper. Following the invasion of Ukraine, the government has also deepened commitments with Western energy giants, in particular Italy's Eni and France's TotalEnergies.

Angola is set to open negotiations with the European Union over a trade deal later this year, Reuters reported earlier this month. Such a deal would be expected to help Angola expand its export base further beyond oil, and aid the EU's efforts to diversify its fuel supply in light of the war in Ukraine.

Lourenco has also overseen an improvement of bilateral relations with the U.S., and has a property in Maryland.

Yet Lourenco's government abstained from the U.N. resolution condemning Russia's invasion of Ukraine earlier this year, while UNITA was vocal in its opposition to Moscow. 

UNITA leader Adalberto Costa Junior has traveled to Washington and Brussels in recent months to establish ties with Western powers ahead of Wednesday's election.

MPLA win likely, but tides turning

The MPLA went into Wednesday's vote ahead in the polls, but many of the country's huge under-25 population are voting for the first time and have increasingly been drawn to the platform of UNITA and its coalition allies in recent years, driven by anger at a lack of economic opportunity.

"The MPLA is very likely to prevail, but the key question is whether they lose their absolute majority. This is key as under Angolan law, as laws can be challenged by the opposition if the majority is under 60 percent," Vines told CNBC via email from Mozambique on Wednesday.

Eric Humphery-Smith, senior Africa analyst at risk consultancy Verisk Maplecroft, agreed that the MPLA is odds-on to pip Costa Junior's UNITA and the opposition coalition, but suggested this may only be the beginning of a greater upheaval in Angola.

"As with other national liberation movements that remain in power in southern Africa, their decline will continue to happen gradually, then suddenly," Humphery-Smith said.

UNITA has drawn together a combination of opposition movements dubbed the FPU (United Patriotic Front) together under Costa's leadership, and attracted a groundswell of increasingly diverse support.

"Attempts by the MPLA to divide and conquer the opposition have largely failed, and the dream team assembled by Adalberto Costa Júnior is clearly a force to be reckoned with," said Humphery-Smith. 

"The FPU platform has lumped together politicians with proven pedigree that can rally the large numbers of voters required to compete with the MPLA."