Barack Obama, the US president, is trying to energize young people to vote to help him keep Democratic majorities in the House and Senate during this year's midterm election on November 2.

But it's a tricky strategy. They're a group of people who never vote in large numbers, especially in midterms.

Obama has concentrated his energy in the last two and a half weeks until the election on them.

He's avoided other typical campaign stops - like union halls and retirement communities.

He's given an interview to Rolling Stone magazine, held numerous rallies on university campuses and participated in town hall events for young people, all in an effort to enthuse a key voting bloc that helped propel him to victory in 2008.

And he's dusted off many of the arguments that worked with young people in the past.

The Democratic National Committee has a new ad out which looks a lot like his ads from 2008, even down to similar music.

The ad starts with Obama at a rally last month at the University of Wisconsin.

He says: "Two years ago you defied the conventional wisdom in Washington. You proved that the power of everyday people was stronger than the forces of the status quo."

But statistics show energizing enough young people to make a difference will be difficult.

Midterms have lower voter turnout than presidential elections.

In the last midterm election in 2006, 22 per cent of eligible young people voted, but 63 per cent of eligible senior citizens cast ballots.

Historically, people aged 65 and older are more likely to turn out to vote.

A new study out by the Washington Post, Kaiser Family Foundation and Harvard University found older people are both more motivated to vote and more unhappy with Washington this year.

Twenty-four per cent of senior citizens give Obama a failing grade as president, while only seven per cent of voters younger than 30 years old say he's failing.

That doesn't bode well for Obama and the Democrats who hold majorities in both Houses of Congress.

At a tele-town hall event at George Washington University on Wednesday, Obama told the audience: "You guys give me confidence. You guys give me hope.

"But I really need you to get out on November 2 because then if all of you vote, I promise we're going to do just great."

He continues his push with young people with another youth town hall meeting broadcast on three different music TV channels, including MTV, on Thursday ahead of a rally at Ohio State University, the second largest school in the US, over the weekend.