ANKARA (Reuters) - A decision by the veteran leader of Turkey's nationalists to back President Tayyip Erdogan's bid for more powers has cost his opposition party so much support that it could be wiped out of parliament, offering Erdogan another potential win.
Devlet Bahceli's Nationalist Movement Party is the smallest of three opposition groups in parliament and the only one that has decided to back a "yes" vote in a referendum on Sunday to consolidate more powers in the presidency.
His position, adopted last year in an abrupt reversal, has so divided the party that it now appears on course to fall below the 10 percent threshhold needed to win seats. It won 11.9 percent of the vote in the last election in 2015.
Erdogan has an incentive to call a snap election swiftly if he secures a "yes" vote in the plebiscite, since the new powers he has long sought would take effect only after fresh elections for president and parliament. If the MHP were to be wiped out, Erdogan would be in an even stronger position, with his ruling AK Party likely to gain an even larger majority in parliament.
"MHP voters feel deceived, they feel they have been fooled," said Sinan Ogan, a leading member of a camp within the MHP that wants to see Bahceli ousted.
"Under Bahceli, the party is likely to face a serious challenge with the (10 percent) election threshold," he said.
Bahceli was a vocal critic of the proposed executive presidency until he abruptly announced last year that he backed the "yes" campaign. He says he now believes a more powerful presidency is necessary to protect the state.
"We are saying 'yes' to the survival of the system, not to a person," he said in a recent speech. "We are saying 'yes' to the continuity of the Turkish Republic."
His opponents in the party say he switched positions over the referendum to secure government help in seeing off a challenge for the party leadership, an accusation he denies.
Shortly after Bahceli backed the "yes" vote, a court and an election body both ruled in his favour to disallow a bid to unseat him as party leader. Opinion polls have suggested that the party would perform better with a different leader, but the MHP's party rules do not allow it to hold a congress to select one until March next year.
Founded by a former colonel who played a role in a 1960 military coup, the MHP espouses a mix of Turkish nationalism and scepticism towards the West. It is virulently opposed to autonomy for Turkey's Kurdish minority.
In the past, its support base included sympathisers of the "Grey Wolves", a nationalist youth organisation that fought street battles against leftists in the 1970s. Mehmet Ali Agca, who attempted to assassinate Pope John Paull II in 1981, was among the youth group's members.
The party is no longer so closely associated with violence after two decades of reform under Bahceli's tenure that brought it more into the mainstream.
But when a group of young nationalists in Istanbul mistook some Korean tourists for Chinese and attacked them in 2015 in retaliation for Beijing's alleged abuse of its Turkic-speaking Uighur minority, he defended the mob.
"What is the difference between a Korean and a Chinese? They both have slanted eyes," he said in a 2015 newspaper interview, prompting widespread ridicule on social media.
Bahceli and the MHP have at times had an uneasy relationship with Erdogan, who in 2009 risked a nationalist backlash by spearheading talks with the militant Kurdistan Workers Party (PKK), which has fought a three-decade insurgency for Kurdish autonomy in Turkey's southeast.
After a ceasefire broke down in July 2015, Erdogan vowed to crush the militants, boosting his popularity with nationalist voters at Bahceli's expense.
Former interior minister Meral Aksener, a two-decade veteran of politics, was seen as the most credible internal challenger to Bahceli until she was expelled from the MHP last year.
She has since become one of the most prominent right-wing voices in the "no" campaign ahead of Sunday's referendum, although she has faced challenges getting the message across.
In February she was forced to give a speech by the light of mobile phones after the power was cut in the hotel hosting the event. A rally last Saturday in Ankara was initially planned for a public square but was moved to a hall after she was denied a permit.
"We decide on (April 16) whether to maintain the republic's values or to hand over the future of the country to a single person," she told the crowd.
Erdogan is hoping that MHP supporters will follow their leader and back the planned constitutional changes. But there remains deep distrust of Erdogan within the MHP, some of whose members worry that he may return to a peace process in the largely-Kurdish southeast.
"I think that my country will head towards a federal system, that it will be divided," said Yelda Dogan, a 45-year-old doctor from the southern city of Antalya, who came to Aksener's rally.
"I will fight until the last drop of my blood for the rejection of the proposed changes."
Editing by David Dolan and Peter Graff