One of the enduring mysteries of U.S. presidential election campaigns - the current 2004 campaign being no exception - has to do with the nation's young people. The estimated 40 million 18 to 30 year olds constitute a huge voting bloc - about one in five eligible voters - with enormous potential influence on the outcome of national elections. But many young people have typically chosen not to vote.

U.S. Representative Rosa DeLauro wants to know what happened to the good old days of student activism. She recently appeared at a Washington, D.C., news conference on the topic of how to motivate young people to vote. "We want to hear on November 2 the voice of young America. It needs to be loud. It needs to be clear. We want you to send the message to Washington that you are out there and that you are involved. That is the democratic process in this country," she says.

Ms. DeLauro's generation was the first to get the youth vote. Student unrest in the late 1960s led to passage of an amendment to the U-S Constitution, lowering the legal voting age from 21 to 18. More young people gained a voice in the political system. About 50 percent of young people ages 18 to 25 voted in the 1972 presidential election.

But the youth vote has declined since then - by nearly 15 percent in presidential elections. Congresswoman DeLauro says more work needs to be done to get young people motivated to vote. "The battle goes on. The battle is still there," she says.

But most American college students don't share that sense there's a political battle to join. They go to class, study late at night, and party on weekends. Election analysts say some students won't take the time to register to vote - even though registering and voting can be done fairly easily by mail.

Margie Klein is with a young voter-turnout group called "Project Democracy." She says that portrait of a college-age voter is incomplete. "In the U.S. we have the highest youth voluntarism rate in history. So clearly young people care. But we're seeing is that a lot of politicians just don't talk about the issues students care about - like the environment, low tuition, good paying jobs. What we're finding is when we talk to students peer-to peer, about the issues they care about, they're much more excited to vote," she says.

Project Democracy is one of about a dozen non-partisan organizations, as well as political and entertainment groups, working on drumming up the youth vote this year. MTV, the hip and influential music-video television channel, broadcasts public service announcements and directs young people to a web site to register. Southland Corporation , which own the 7-Eleven nationwide convenience store chain, is also involved - as are various rock music stars and Hollywood celebrities. Coffeehouses, concerts, radio and TV stations somewhere, these days, there's a message urging young people to vote.

But some critics suggest the campaign may be overkill. Young people are already motivated, they say. Allison Aikle, a spokeswoman for the College Republicans predicts the youth voter turnout this year will be big because of life-and-death issues like the war in Iraq and the September 11, 2001 terrorist attack: "We live in a different world since 1972 and the 2000 election. We've had all sorts of things that have changed our country. Students are becoming involved because of those things: September 11, the Florida [election] recount [in 2000]. We see that every vote matters. Because of those things, students have decided there's a reason to get involved now," she says.

There are other signs of growing student interest in voting. Ivan Vrishberg, a spokesman for "The New Voter's Project," a non-partisan youth registration organization, says his group has had a lot of success. "Young people are expressing renewed interest into turning out to vote and all of the research shows incredible increases in the level of the interest they're showing the election, the amount of attention they're paying to the election and certainly the amount of voter registration. We're active in 20 states across the country but focused on six states - where we've already registered 200-thousand young, 18 to 24 year old voters to vote and have built a voter file of over a million young voters - just in those six states," he says.

Youth voter turnout may actually reach a new high this year, according to some analysts. A recent Harvard University study found that 62 percent of young people now say they will vote in November.

That seems to be a common view among this group of students I talked to recently on the campus of George Washington University in Washington, D.C. "I think 'MTV' and 'Rock the vote [a decade-old student registration campaign] and other programs like that are doing a pretty good job at making kids come to the realization that voting is cool and is in. So it's pretty well accepted," said one.

And what issues get students excited enough to vote? Surveys show they're concerned about the rising cost of tuition, the state of the environment, and the availability of jobs. Mark Kornbluh is a professor of political science at Michigan State University in East Lansing, Michigan. He says there's one issue above all that has many students worried. "If they're 18 and 19 years old, they may face a renewal of the draft. You can't over-emphasize the importance of this. I think when kids today think about this: the foreign policy [issue] that really hits home personally is not a hard case to make to them," he says.

Other observers point out that when dealing with many young people, it's hard to predict just what they're going to do. Some may register and never show up to vote. They may be motivated one day and the next day just decide to skip it.

So: many potentially decisive votes may be cast. Or they may not. In that sense, the prospects for the youth vote this year seem familiar - volatile and unpredictable.