* Bouteflika looks set to win another five-year term
* Opposition parties ready to boycott April 17 vote
* Questions over how Bouteflika will campaign, govern
By Lamine Chikhi and Patrick Markey
ALGIERS/TUNIS, March 7 (Reuters) - Algerians may not have been shocked to learn their ailing President Abdelaziz Bouteflika would run for re-election after 15 years in power, but the way he let them know was a surprise.
After months of speculation, the 77-year-old leader, who suffered a stroke last year, gave no live television or radio speech to declare his candidacy, leaving his prime minister and the state news agency to announce it last week.
On Monday, Bouteflika registered at the Constitutional Council 24 hours before the deadline, appearing briefly on state television to speak in public for the first time in months.
Credited with leading Algeria out of the 1990s civil war between security forces and Islamists, he looks almost sure to win, with support from his powerful National Liberation Front (FLN) party, its allies and army factions.
Another Bouteflika term would remove immediate uncertainty about the future of Algeria, a major African oil supplier and an ally in Washington's war on Islamist militants who have extended their roots in North Africa thanks to chaos in next-door Libya.
But for all the official insistence Bouteflika is in good shape, his scarce appearances have prompted doubts about how he will campaign, what happens if he falls ill and who succeeds him if his health forces him to step down in his fourth term.
Even in announcing Bouteflika's candidacy, Prime Minister Abdelmalek Sellal did little to quash doubts over his health when he said the president did not need to campaign himself as there were plenty who could do that for him.
"You can count on one hand the number of times that Bouteflika has appeared in public in the last year," said Geoff Porter, a North Africa specialist at the Combating Terrorism Center at West Point. "As far as exercises in democracy go, the 17 April elections are going to be a strange one."
CIVIL WAR MEMORIES
Algerians, still scarred by the civil war, which cost 200,000 lives, staged no popular uprising against the status quo similar to those elsewhere in the Arab world in 2011.
Politics remains in a time-warp shaped by the struggle against colonial power France which led to independence in 1962.
Since then, a cabal of FLN party veterans, business elites and army generals, known as "Le Pouvoir", French for "The Power", has called the shots, operating behind closed doors.
In recent weeks, backroom sparring between Bouteflika's clan and DRS intelligence service chief General Mohamed Mediene, long a political kingmaker, burst into the open, with politicians and generals aiming thinly disguised barbs at one another.
Much of this reflected efforts by Bouteflika's faction to neutralise Mediene's political influence before the president announced his candidacy for a fourth term, analysts say.
Bouteflika's men appear to have won the day. Several intelligence generals have been sacked or transferred, while the president's allies hold key posts in the army and the cabinet.
One Bouteflika associate, General Ahmed Gaed Salah, chief of staff and vice defence minister, now heads a commission that approves military promotions. Political sources say this post can be used to curtail the DRS's role in politics.
In 2012, Bouteflika suggested time was over for his generation of leaders, but he has only consolidated his grip.
"It is the beginning of the end for Le Pouvoir in Algeria because Bouteflika is Le Pouvoir now," a Western diplomat said.
Algerian political cartoonists have mocked the candidacy of a veteran president who has almost vanished from the public eye.
One sketch in the El Watan daily shows the Oscars Award for best movie special effects with nominees listed as: "Gravity", "Iron Man 3", "Star Trek", and from Algeria, "The Fourth Term".
Bouteflika's allies say he is a stabilising figure in a region where Libya demonstrates the risks of chaos three years after NATO-backed rebels ended Muammar Gaddafi's 42-year rule.
Once he is re-elected, the constitution might be amended to create posts for one or even two vice presidents to manage politics and security, a source close to the presidency said.
"He will likely leave power before the end of a five-year term, and a vice president will take over," the source said.
Sellal, 66, who as prime minister ran most day-to-day affairs when Bouteflika was ill, might be one contender for vice president. Algeria's police chief, Major-General Abdelghani Hamel has also emerged as a possibility.
Though weakened, the DRS intelligence agency remains an influential player in Algeria's opaque politics.
"A fourth term by Bouteflika will not end the conflict," said Eurasia Group North Africa specialist Riccardo Fabiani. "Regime stability will depend on Bouteflika's health, and regime factions manoeuvring to decide who will succeed the president."
When other Arab countries rose in revolt, Bouteflika eased discontent by distributing loans, housing and higher salaries.
As long as global oil prices remain around $100 a barrel, the OPEC producer, with around $200 billion in foreign reserves, may be able to sustain such generous public spending.
In the longer term, Algeria desperately needs economic reforms to fight its budget deficit, loosen foreign investment restrictions and attract investment in its declining oil sector.
Opposition parties, which are much weaker than the entrenched FLN, have threatened to boycott the April 17 vote, saying the president has an unfair advantage.
There are five other contenders, but some opposition politicians, such as Said Saadi, are staying out of the race.
"I will not run because the election is closed. Bouteflika's men will supervise the vote," he said. "The game is closed."
Three parties, including Saadi's RCD and the Islamist MSP party, have joined forces to urge a boycott of the vote.
Campaigning starts on March 23, but Algerian voters don't know whether Bouteflika will become more visible to the public.
"Even if, as his supporters say, he still has all his mental faculties, how will he campaign?" West Point's Porter said.
"Presidents are elected for five-year terms. If he doesn't campaign himself, how will the electorate know he has the stamina to complete his term?" (Reporting by Patrick Markey; Editing by Alistair Lyon)