MANCHESTER, N.H. — A 76-year-old great-grandfather who gives eye-glazing speeches on monetary policy, displays a crotchety streak and disappears from the Republican campaign trail for days at a time to rest is captivating young voters.

Texas Rep. Ron Paul’s libertarian message of less government, personal liberty and ending U.S. military involvement overseas clicks with young people, who are supplying zest for his stronger-than-expected presidential campaign. Nearly half of all voters under 30 went for Paul in the first two states to vote, helping to propel him to a second-place finish in the New Hampshire primary and third place in Iowa’s leadoff caucuses.

Why would young people gravitate to the oldest guy in the field?

“Freedom is a young idea,” says Eddie Clearwater, a 22-year-old Des Moines photographer who attended a Ron Paul party in Ankeny, Iowa, earlier this month. “All of his policies are such a good, radical change. It’s what we need.”

Paul’s campaign events are charged with an energy that any politician would love, attracting an eclectic band of youthful activists ranging from preppy college students to blue collar workers to artists sporting piercings and dreadlocks. At his party after the New Hampshire primary, there were spontaneous chants of “Ron Paul Revolution! Give us back our Constitution” and “President Paul! President Paul!”

A tickled Paul told the cheering crowd: “Freedom is a wonderful idea, and that’s why I get so excited. But I really get excited when I see young people saying it.”

“We are dangerous to the status quo of this country,” said Paul, who seems to relish making political mischief and has taken on the role of a feisty attacker in some of the GOP debates.

While Paul is unlikely to win the GOP nomination and young voters make up a relatively small slice of the electorate — 12 percent in the New Hampshire primary and 15 percent in the Iowa caucuses — their lopsided support has made Paul a force to be reckoned with in the 2012 campaign. And it could prompt a more serious consideration of his views by Republicans and Democrats alike.

“Ron Paul is bringing unorthodox ideas to the marketplace that don’t fit with the conventional pillars of either political party,” said Matthew Segal of OurTime.org, a nonpartisan group that promotes political participation among young people. “And because young people today are a uniquely independent-minded generation, he’s resonating with them.”

According to polling-place interviews conducted for The Associated Press and the television networks, 53 percent of under-30 voters in New Hampshire and 35 percent in Iowa identified as independents or something else. They are not establishment Republicans, and not as supportive of the tea party movement as their elders.

Paul’s critics sometimes poke fun at his popularity with that age group, suggesting they are mainly attracted to his anti-war message and support for liberalizing drug laws, which are both far outside the Republican mainstream.

But the stereotypes belie the reality facing young people.

Polling-place interviews in New Hampshire and Iowa found younger voters in both states were just as likely as older voters to cite the economy as their top concern. Paul won among younger voters who said the economy is the most important issue. Overall, he drew 46 percent of under-30 voters in New Hampshire, beating front-runner Mitt Romney by a full 20 percentage points in that age group. In Iowa, he got 48 percent of the youth vote, 12 points higher than top-two-finishers Romney and Rick Santorum combined.