By Ingrid Melander
PARIS (Reuters) - French voters cast ballots on Sunday in runoffs for regional elections that will show whether the far-right National Front can turn popularity into power.
Marine Le Pen's party achieved a breakthrough last week by taking the lead in the first round of the vote, drawing strength from fears over Europe's refugee crisis and the Islamic State militant attacks that killed 130 people in Paris a month ago.
"For me, she is going to win. Maybe it will make all those politicians stop and think," said voter Evelyne Risselin in Le Pen's electoral home base Henin-Beaumont in northern France.
But the anti-immigrant, anti-European Union National Front (FN) was by no means certain to take any of the 13 regions.
The outcome will depend largely on what left-wing voters will do after the ruling Socialist party withdrew from the race in the two regions where the FN was performing best - the north where Le Pen is a candidate, and the southeast where her niece Marion Marechal-Le Pen is running.
The Socialists urged their supporters to back Nicolas Sarkozy's conservatives in those two constituencies to keep the FN out of power, and a series of opinion polls have shown that voters might well be heeding that call with the conservatives marginally ahead in both areas.
"Voters should not be treated like children, nor be terrorised," a smiling Marine Le Pen told reporters after casting her vote in Henin-Beaumont.
The Socialists fear that some of their supporters might stay home rather than go and vote for the party of Sarkozy, who is widely despised by the left. Just under one in two registered voters turned up at the polling stations last week.
But turnout stood at 50.54 percent at 5 p.m. (1600 GMT). This was seven percentage points higher than at the same time in the first round, when full-day turnout was 49.91 percent, showing increased interest in the run-off with higher stakes.
"VERY TIGHT RACE"
Opinion polls in some regions forecast a close finish, especially in the southeast targeted by Marechal-Le Pen.
"The only thing that is certain is that it will be a very tight race," political analyst Joel Gombin, a specialist on the far-right, said of the run-offs.
First estimates of the outcome were due at 1900 GMT, when voting stations close.
Much attention will also be focused on the northeast Alsace-Champagne-Ardenne-Lorraine region, where the Socialist candidate rejected his party's call to drop out of the run-offs.
The run-offs were seen as testing of the waters for all three front-runners for the 2017 presidential elections, the Socialists' Hollande, ex-president Sarkozy and Le Pen.
The FN has never managed any constituency larger than a few small and medium-sized towns, and winning a region is central to its strategy to try and convince voters it could eventually be trusted to govern the country.
In local elections in March, the National Front failed to win any department in the run-offs despite a strong showing in the first round.
That was partly because it was unable to attract other parties to strike alliances with between the two rounds.
For Sarkozy, who was hoping a landslide victory would raise his chances for re-election in 2017, the first round was a severe disappointment that weakened his hand within his party, The Republicans.
How many regions the conservatives eventually win will be pivotal to the struggle for power within the party.
The Socialists, who currently govern in all but one of the 22 regions under a map that was redrawn for this election, were sure to suffer big losses of popular vote. But, paradoxically, the FN's strength, by weakening Sarkozy's conservatives, could help the Socialists cling to more regions than they hoped.
Socialist President Francois Hollande voted in his electoral home base in Tulle, southwest France, amid tight security following the Paris attacks on Nov. 13.
Voters took selfies with a relaxed Hollande, who scored a big diplomatic victory on Saturday by getting almost 200 countries to agree a pact to limit global warming.
(Additional reporting by Morade Azzouz and Geert De Clercq; Editing by Mark Heinrich)
