Led by the charismatic Recep Tayyip Erdogan, the Justice and Development Party (AKP) is expected to grab an easy victory in Sunday's polls,-- with about 45 percent of the vote, according to pollsters, enough to form its third one-party government since 2002.
With its win considered a foregone conclusion, questions linger over whether the AKP will secure an overwhelming majority in parliament, enabling it to forge ahead with a constitutional overhaul at a time when Erdogan's increasingly aggressive style has raised suspicions over his future path.
The main opposition centre-left Republican People's Party, rejuvenated under a popular new leader, Kemal Kilicdaroglu, is said to stand a chance of increasing its vote from 20 to 30 percent, posing its strongest challenge yet to the AKP.
With the Nationalist Action Party and Kurdish-backed candidates also expected to make it to parliament, the super majority Erdogan craves appears off limits for the AKP, pollsters say.
His campaign marked by harsh verbal skirmishes with opponents, Erdogan has hinted he may even drop plans to rewrite the constitution, the legacy of a 1980 coup, if the AKP fails to secure a strong enough majority to go ahead on its own.
"The first step (after the elections) is the constitution but this depends on parliamentary arithmetics... If parliamentary arithmetics do not permit, the existing situation will go on," he said in a recent interview on Kanal D television.
The AKP is seeking at least 330 seats in the 550-member house, which would allow it to amend the constitution without the support of other parties and put the text to a referendum.
A two-thirds majority of 367 seats would enable it to pass the amendments unilaterally.
Some opinion polls have suggested the AKP may hit the 50-percent mark and come within reach of the 330 seats.
Erdogan has refused to say what the constitutional reform would entail, fanning speculation with his advocacy of a presidential system for Turkey -- presumably with himself at the helm.
"I have many dreams but I'm unable to realise them as fast as I'd like to. There are many obstacles," he told Kanal D, complaining of the bureaucracy and the judiciary.
Erdogan has won praise for economic stability after years of crisis, and democratic reforms that have led Turkey into membership talks with the European Union and humbled the once-omnipotent military.
The former Islamist however has become increasingly intolerant to criticism: inclined to see a conspiracy behind any dissent, he routinely attacks the media and condones police clampdowns on street protests.
Dozens of journalists have landed in jail as part of massive probes into alleged coup plots, hailed initially as a long-awaited move to curb the army after its ouster of four governments in the past.
AKP opponents are alarmed also over creeping restrictions on the Internet and alcohol sales, and an unprecedented outbreak of compromising wiretaps and videos of opposition figures circulating online.
Adding to Erdogan's woes, Kurdish nationalists have become more defiant, demanding autonomy and a negotiated solution to a 26-year insurgency that has claimed some 45,000 lives.
Kurdish-backed candidates running in the election as independents to circumvent a group's requirement for at least 10-percent of the vote nationally, are expected to increase their seats from the current 20 to up to 30.
The Kurdish conflict is looming large for Ankara despite a series of reforms that have widely broadened Kurdish cultural freedoms.
Jailed Kurdish rebel leader Abdullah Ocalan, who retains his influence despite being behind bars since 1999, has warned that "all hell will break loose" after the polls, unless sporadic contacts officials have had with him in prison are upgraded to full-fledged negotiations for a settlement.