What makes Newt run?

Call Newt Gingrich a spoiler. Call him unrealistic to the point of delusion. Talk till you're blue in the face about how the GOP nomination is statistically out of reach.

All that misses the point, say those who've known him longest and best. The point, they say, is something Gingrich himself put into words this week, talking about the things that bring him "deep inner satisfaction."

"I love the process of interacting with people; I like learning," the 68-year-old candidate told a group of teens as he campaigned in Illinois. "In my mind every day is cool. I'm still here."

That love of the game, say longtime Gingrich-watchers, explains why, even without a credible path to the nomination, Gingrich is resisting calls to drop out. The former House speaker, they say, simply relishes politics -- the pageantry and the policy-making.

Supremely confident of his own significance, he's an egotist, but an idealistic one, said Tom Glanton of Dallas, Ga. Glanton met Gingrich in Carrollton, when Gingrich was teaching at West Georgia College.

He gave Gingrich $250 toward his first run for Congress in 1974. He also memorized the younger man's Quixotic prescription for a career in public service. "If you’re going to be successful in politics, you must have a glorious quest."

Gingrich, the self-professed candidate of "big ideas," clearly gets a charge from speaking in front of a group, say those who have charted his almost 40-year ride on the political roller coaster.

"I think he genuinely enjoys the process," said Larry Sabato, head of the Center for Politics at the University of Virginia.  "My God, he has ready-made audiences, not just of people but cameras, for his every word, all day long," he said. "This is heaven."

Sabato also sees in Gingrich an "eternal optimist," the kind of guy who "always finds the pony in the pile of manure."

"He’s always been like that," he said. "As unrealistic as it is in many respects, it has its advantages when you run a long-shot campaign."

Gingrich stumped in Louisiana Friday ahead of the state's March 24 primary. Before that it was a swing through suburban Chicago. Gingrich and his wife, Callista, are expected to take the weekend off before returning to the Bayou State Monday to continue pursuing their southern strategy.

Picking up a big chunk of Louisiana's 46 delegates is important for Gingrich. He lost key primaries Tuesday in Mississippi and Alabama to a northerner: former Pennsylvania Sen. Rick Santorum, who is running strongly in Louisiana. On Tuesday, Gingrich barely managed to edge out former Massachusetts Gov. Mitt Romney, who holds a substantial lead in the national delegate race.

Even though his staff had declared that Gingrich must win Mississippi and Alabama to remain viable, he didn't miss a beat, barely acknowledging the calls for his exit. In his address to teens in Illinois, he encouraged them to follow their own hearts and resist outside pressure.

"It's not about being true to your friends, or being acceptable to your peers," Gingrich said. "It's who are you, and are you comfortable with you?"

Longtime friend and former adviser Matt Towery, CEO of the polling firm InsiderAdvantage, said it's not just the love of politics that keeps Gingrich in the game. It's also "a love of policy."

"I think he has moved on to this idea that, ‘If I can't win the presidency, I'm going to force people to talk about these broad issues they’re not discussing,'" said Towery, who has known Gingrich since the late 1970s. "His sheer love of talking about policy and trying to influence the national political discussion becomes more important."

To those observations, former Gingrich aide Rich Galen added this: "One of the things I learned from Newt long ago is his absolute conviction, and one I think is correct, that people who have otherwise good ideas fail largely because they give up too early."

After all, both Galen and Towery noted, Gingrich worked for nearly a decade and a half to become speaker of the House in 1994.

"He started thinking about that seriously in the early 80s," Galen said. "It took him 14 years to accomplish it."

This campaign, during which Gingrich has been declared finished more than once only to bounce back, also echoes the extraordinary highs and lows that have marked his entire career.

That's a storyline that resonates with the public said Charles Bullock, who holds the Richard Russell professorship in political science at the University of Georgia. "We flock to see movies and read books about people who are dealt a bad hand, knocked down and get back up."

Some speculate that Gingrich is fueled by a desire to repay Romney for the barrage of attack ads the pro-Romney PAC Restore Our Future unleashed on him in Florida.

Towery said that after all this time in the game, Gingrich isn't easily ruffled. Even so, he said, the ferocity of those ads, which blasted Gingrich's ties to mortgage giant Freddie Mac, took him by surprise.

"The degree of those campaign ads has come as a shock to Newt, with what they said," Towery said.

If nothing else, staying on the stump allows Gingrich the opportunity to criticize Romney in front of a national audience, Bullock noted.

As a student and teacher of history, Gingrich also has an eye toward shaping his profile for posterity, said Dan Schnur, director of the Jesse M. Unruh Institute of Politics at the University of Southern California. "This campaign," he said, "may be Gingrich's last chance to frame his legacy."

Galen, too, acknowledged that 2012 may be Gingrich's last sustained foray into the political limelight. "At this point in his life," said Gingrich's former aide, "he doesn't really have anything else to do."

-- Staff writer Daniel Malloy contributed to this report.