European Union leaders are fighting a rearguard action to prevent a low turnout at a European Parliament election that could favor extremists and raise questions about the assembly’s legitimacy.

An opinion poll last month suggested only 34 percent of the more than 375 million eligible voters were likely to take part in the election on June 4-7 and few understood the issues.

Since then, European politicians have been trying to explain what is at stake in campaign rallies, on television and radio, and in webcasts and blogs.

The Parliament’s president, Hans-Gert Poettering, sent members of the assembly (MEPs) out to campaign this month with a rallying cry: “Together we have achieved much and we must now again seek the confidence of the electorates.” His message focused on the simple need to explain why the EU and the European Parliament are important, as did European Commission President Jose Manuel Barroso’s appeal to voters. “Your vote matters. Because your choice will help shape the European Union’s course of action for the next five years,” he said in a video message on his website.

But everything points to a low turnout which could favor nonmainstream parties and further shake confidence in the EU, which represents nearly 500 million people in 27 countries.

“I’ve never seen such efforts to get people to the polls but it's hard to say what effect it will have,” Roland Freudenstein, director of the European Policy Center in Brussels, said.

Luc Couturier, a 55-year-old French businessman, merely shrugged his shoulders when asked whether he would vote.

“What difference will it make if I don't vote? Nothing much is going to change whether I vote or not,” he said.

The Parliament has important roles in shaping European legislation, approving the EU’s budget and exercising democratic control over EU institutions.

But there are many reasons why turnout has sunk from 62 percent at the first European Parliament election in 1979 to a record low of 45.5 percent at the last election in 2004. Many voters feel no direct impact on their daily lives from an assembly that works in Brussels and the French city of Strasbourg, even though it has a role in shaping laws on matters ranging from the environment to mobile phone roaming charges.

The Parliament is also involved in passing laws to help combat the global economic crisis, but the EU’s response to the downturn has been widely criticized.

“The economic crisis is one element in pushing people to stay at home,” said Thomas Klau of the European Council of Foreign Relations. “People have noticed the EU as a whole has not been very dynamic in the way it’s responded to the crisis.” Few voters understand the EU system under which Parliament shares power with the Council of Ministers (EU leaders) and the executive Commission, does not directly elect an EU president or government and lacks traditional government-opposition rivalry.

MEPs find it hard to get their message across because there are few pan-European media or political parties, and national parties have little interest in European elections. The vote is also complicated by the fact that many of the candidates for the 736 seats are little known and campaign on local issues. Further complicating matters, the assembly’s powers will change if the EU’s Lisbon reform treaty is approved.

Most analysts say a low turnout would favor nonmainstream parties including nationalists and forces hostile to the EU such as the British National Party and the UK Independence Party.

“People say the European Parliament doesn't matter so use their vote where they wouldn't normally, outside mainstream politics, but I don't think there'll be a drastic change,” said Hugo Brady of the Center for European Reform in London.

A low turnout could prompt questions about the legitimacy of the Parliament and might be portrayed as a vote of no confidence in the EU. But analysts say low turnouts in US elections do not undermine a president's legitimacy and cite opinion polls that show Europeans still have faith in the EU.