* West increasingly concerned over Albanian democracy
* Top electoral body short-staffed after political row
* PM bidding for third term, polls suggest defeat
A united left in Albania seeks to unseat Prime Minister Sali Berisha on Sunday in an election watched closely by the West less for the result than the conduct, given rising concern over the state of democracy in the NATO country.
Berisha, a fiery former cardiologist, is bidding for a third successive four-year term, unprecedented in Albania since the fall of its hardline communist regime in 1991.
But the threat of a disputed result is rising, after a political row left the country's top electoral body, the Central Election Commission, short-staffed and unable to certify the result. A court will do so instead.
The United States has warned of an impending "charade" and Western diplomats say there are signs of a campaign to coerce voters. Since 1991, Albania has never held an election deemed fully free and fair, and failure again would further set back its ambitions to join the European Union.
Opinion polls are unreliable, but point to a narrow victory for the opposition Socialist Party of former Tirana mayor Edi Rama, 48, who has been buoyed by an alliance with a small leftist party previously in coalition with Berisha.
Rama lost the last election in 2009, called protesters into the streets and four were shot dead by security forces.
Berisha has dominated Albanian political life since the collapse of its Stalinist regime triggered a break-neck and sometimes violent transition to capitalism. At 68, defeat on Sunday could spell the end of his career.
President Bujar Nishani called for maturity.
"Let us pay due attention to the vote's importance for our country's very important relations with the world," he said in a televised address. "Because our present and future freedom, well-being and fate are closely linked to it."
Some of the half a million Albanian workers in neighbouring Greece returned by bus to vote. Including the migrants, there are 3.27 million eligible voters, fractionally more than the official resident population of Albania of 2.8 million people.
From Albania's rugged Alps in the north, down an Adriatic coastline still undiscovered by Western tourists, to the Ionian sea off Greece, polls open at 7 a.m. (0500 GMT) and close at 7 p.m. (1700 GMT).
Official results are due in the evening, but may be delayed by party frictions within the counting stations.
Rama withdrew the opposition's three representatives from the seven-member Central Election Commission in April after the coalition government sacked a member whose party had allied with the Socialists for the election.
Police said they would deploy helicopters to watch trouble spots and army commandoes were mobilised to guard embassies.
The Socialists and Berisha's Democratic Party differ little on Albania's strategic goal of joining the EU or its staunchly pro-Western policy. But their confrontational relationship does not sit easy with Brussels or Albania's NATO allies.
The EU says the election is a "crucial test" of Albania's democratic institutions and its progress towards the 27-nation bloc, which Croatia will join in July. Albania applied four years ago to come aboard but has not yet been made an official candidate for membership.
The next government will take on an economy feeling the effects of the crisis in the euro zone, particularly in Greece and Italy where some 1 million Albanians work to send money home.
While Albania avoided recession, remittances are down and the World Bank is concerned about the rising public debt and deficit.
It could yet be months before a new government takes office, with challenges to the election result almost certain. A system by which party members count the ballots has repeatedly led to disputes and delays.