* Erdogan widely expected to win presidential vote
* Coastal resorts traditionally opposition strongholds
* Holiday-makers urged not to skip voting
By Daren Butler
BODRUM, Turkey, July 16 As families splash in the sea and lounge in the sun, thoughts of politics and civic duty are a world away for most Turks holidaying on the Aegean and Mediterranean coasts.
Only the most committed opponents of Prime Minister Tayyip Erdogan leave the beach to queue in a sweltering council building nearby to register to vote in next month's presidential election to prevent what they see as the country's slide towards authoritarianism.
They fear others enjoying the annual summer exodus from Turkey's crowded cities to coastal resorts will risk a fine for not voting rather than going home or signing up locally, giving Erdogan the boost he needs to win the first round on Aug. 10.
"We're here to protect the secular state founded by Ataturk from a prime minister who wants to establish an Islamic country," said Mehmet Turan, 39, who was registering to vote in Bodrum rather than interrupting his long summer break to vote in Istanbul where he usually lives.
He is among thousands of people with holiday homes in the summer playgrounds of Bodrum, Cesme and Marmaris that are popular with opposition sympathisers who have applied for a change of address to enable them to vote while away.
On its website, the opposition CHP - which Erdogan has dubbed the "party of the beaches" - has urged those with summer homes to register the addresses, instructing them on how to do so, and has sought to persuade others to return home to vote.
An official at the local election board said an additional 12,000 voters had registered in Bodrum before a deadline last week, increasing the electoral roll by more than 10 percent.
"The element which would strengthen Erdogan's prospects of being elected in the first round the most is a low participation rate," said veteran political columnist Cengiz Candar.
"The timing of the election during the summer holiday ... is a factor ... It is essential for the (opposition) CHP and MHP to put their power behind their joint candidate and mobilize their voting masses."
Since his centre-right, Islamist-rooted AK Party came to power in 2002, Erdogan has built huge support among conservative Muslims, many of them poor, who had felt treated as second-class citizens in a constitutionally secular society.
Barred by party rules from serving a fourth term as prime minister, few doubt he will win the presidency he has long coveted in the August election, if not in the first round on Aug. 10, then certainly in a run-off two weeks later.
But his inflammatory language and autocratic instincts when threatened - evidenced by bans on Facebook and Twitter during a corruption scandal earlier this year and by a heavy police crackdown on protests last summer - have alienated large segments of society and left Turkey deeply polarised.
In its coastal resorts, thronged during the summer months with European tourists as well as holidaying Turks, many are also suspicious of the encroachment of religious values in public life in the mainly Sunni Muslim nation.
"We went to a lot of trouble to do this because we want to stop the prime minister becoming president," said Ahmet, 66, a retired Ankara resident in a T-shirt and shorts, queuing to change his address at the local council office.
"The political system has collapsed. We are heading towards a dictatorial regime."
"PARTY OF THE BEACHES"
Erdogan bristles at the notion that he is anything other than a democrat. He has tamed the power of a military that intervened to topple four governments in the second half of the 20th century and done more than any previous Turkish leader to deepen the rights of Kurds, the country's largest minority.
The ruling AK Party he founded in 2001 itself united a broad spectrum of nationalists and social and economic reformers, as well as elements of a conservative religious party pushed from power by the army in 1997.
But what critics see as his religiously-motivated interference in private life - from tighter restrictions on alcohol and advice on how many children women should have, to his moral outrage last year at male and female students sharing apartments - has increasingly raised hackles.
Turkey's "Kemalists" - upholders of the legacy of Mustafa Kemal Ataturk, founder of the modern secular republic - see their ideals being eclipsed by a new more 'Islamic' Turkey, forged by Erdogan and the new ruling class around him.
It is an antagonism he does not hesitate to play on.
Last August, photographs emerged of him in a small yacht touring the Bodrum peninsula - where he himself holidays - with a group of bureaucrats, apparently, according to newspaper reports, taking note of irregular construction activity.
He later told journalists that inspections and court cases may follow, seen as a threat to members of the secular elite, whose villas and luxury condominiums hug the shoreline.
"I am proud to call myself a Muslim but Turkey has been moving away from the West and has become more Islamicised," said Eyup Turedi, seeking customers for boat trips near Bodrum's main pedestrian thoroughfare behind its café-lined beach.
"It is the gateway to Europe and it is still modern, but if the election results see it moving in the opposite direction, it will be Turkey's loss."
The main opposition CHP, the secularist party founded by Ataturk, won just over 50 percent of the vote in Bodrum in municipal elections on March 30, a vote seen as a referendum on Erdogan's rule. The AK Party polled less than 10 percent.
But the picture was different in the wider country, with the AK Party dominating the electoral map and retaining the main cities of Istanbul and Ankara, despite the corruption scandal plaguing Erdogan's government and last summer's protests.
For the presidential race, the CHP has united with the nationalist MHP party in fielding Ekmeleddin Ihsanoglu as its candidate, a diplomat and academic who was at the helm of the Organisation of Islamic Cooperation for nine years until 2014.
But its choice of Cairo-born Ihsanoglu, 70 - who has dedicated a large part of his life to promoting Islam - has left some CHP supporters bemoaning the lack of a true secularist candidate in the race, and uncertain as to how to vote.
"He is too passive and too old. If we want Turkey to have a future we have to give the youth a chance," said Kadri Aksel, 57, a construction engineer registering to change his address. (Additional reporting by Ozge Ozbilgin in Ankara; Editing by Nick Tattersall and Anna Willard)