Sen. Marco Rubio (R) greets supporters after speaking at a campaign event in Las Vegas on Oct. 8. (David Becker/Reuters)

After watching Marco Rubio deliver his uplifting stump speech at a retirement community here the other night, Howard Dickerson, 80, turned to his wife, Alice, and said, “He’s the one.”

“He’s got the whole package,” Dickerson said. “He leaves you feeling like you’re in good hands. I am sold on him, I’ll tell you.”

The next day, a similar reaction: “He speaks from the heart — and it’s smooth, without the hems and haws how most Americans speak,” Marcia Friedman, an artist and writer, said after seeing Rubio campaign at a Cuban restaurant here. “He just exudes a trustworthiness.”

As Republicans harp on the vulnerabilities of their leading presidential candidates — Jeb Bush’s dynastic pedigree and campaign-trail mishaps, for instance, or Donald Trump’s and Ben Carson’s preparedness to be commander in chief — they are beginning to give Rubio a serious look.

The crowds at Rubio’s events are bigger and more enthusiastic than before. His debate performances were widely acclaimed. He is ticking up in the polls ever so slightly. To Republicans in search of an electable standard-bearer to win back the White House, Rubio represents a basket of potential — the GOP’s great Barack Obama-like hope.

Bob Butcher, center, wipes a tear from his eye as Sen. Marco Rubio speaks at a campaign event in Las Vegas on Oct. 8. (David Becker/Reuters)

Yet Rubio is largely untested on the national stage. He has not faced the intense media scrutiny that front-runners attract. His rivals are only beginning to attack: Trump called him “a lightweight,” while Bush belittled his leadership experience and spotty Senate attendance record.

Perhaps the biggest obstacle for Rubio are his parallels with Obama. It has become Republican gospel that Obama is in over his head as president, so it remains to be determined whether the party would nominate in 2016 its own charismatic, first-term senator without executive experience.

Unlike some of his opponents, Rubio has no natural base of support, nor has he settled on a particular state that he sees as ripe for an early win. Rubio is raising significantly less money than Bush and some other candidates — and though his campaign boasts of its frugality, the downside is his organization on the ground is more shallow.

The question this fall, then, is whether Rubio can go the distance. Will his momentum, as ephemeral as it may seem today, eventually grow into a durable and lasting movement? Can Rubio fulfill his promise, as encapsulated by Time magazine’s 2013 cover anointing him “The Republican Savior”?

“Marco Rubio is in position to be the Republican nominee,” said Steve Schmidt, a strategist on the George W. Bush and John McCain presidential campaigns. “The challenge is to be prepared for the moment in time where his numbers climb rapidly, which is in my view almost certain to happen.”

To break out from the big GOP pack, many candidates have chased headlines — rushing to the aid of imprisoned Kentucky clerk Kim Davis or to disavow birthright citizenship.

Not Rubio. This 44-year-old son of Cuban immigrants is a storyteller and believes in the persuasive power of his personal narrative. His campaign has been cautious, with each potential move weighed as to whether it serves his own story.

Sen. Marco Rubio and a supporter pose for a photo at a campaign event at a Cuban restaurant in Las Vegas on Oct. 9. (John Locher/AP)

“You can go after the latest shining object or stay focused and execute your plan,” said Nevada Lt. Gov. Mark Hutchison, Rubio’s state campaign chairman. “He needs to stay focused.”

On Thursday night in Summerlin, a master-planned community on the outskirts of Las Vegas, Rubio cast himself as an agent of change. “If we keep electing the same kind of people, the next person in line, the person they tell us we’ve got to vote for, nothing is going to change,” he said.

If that sounds familiar, that’s because it is. On the stump in October, Rubio gives nearly the same speech he gave in downtown Miami when he first announced his presidential campaign in April.

One might call this boring or robotic, but the Rubio team sees it as consistent and disciplined. He is trying not to peak now. Rubio’s strategy is to become the momentum candidate at just the right moment: Not in October, not in November, but right around New Year’s, before Republicans start caucusing and voting on Feb. 1.

A talented communicator, Rubio can sweep audiences off their feet. During a recent luncheon speech, for example, a chef and server came out from the kitchen to listen and record videos of him. But his allies see a risk in over­exposure, concerned that the chills his crowds feel might wear off if he is in the spotlight month after month.

“Timing is an underappreciated virtue in presidential campaigns,” Schmidt said. “The issue for the ultimate nominee of the party is not about getting to the top of the polls; it’s maintaining your position at the top of the polls when that moment comes.”

Rubio’s performances are rehearsed orations of policy pronouncements and personal anecdotes. He peppers his talks with catchy, relatable examples. When he expounds on how technology is disrupting the economy, he draws knowing nods when he says that Uber has become a leading transportation company without owning any vehicles.

Explaining his plan to overhaul higher education and expand vocational training, he says, as he did at a business luncheon on Friday: “We know for a fact that a welder makes a lot more money than a philosopher, but we graduate a lot of people with philosophy degrees and we stop teaching people how to be welders or airplane mechanics or technicians or machinists or pipe fitters or plumbers or electricians.”

Jeff Hartson, 54, a handyman, said, “I like just about everything he stands for. I’m really optimistic about Marco. . . . He doesn’t come from wealth or privilege. He understands why the United States was founded and why it’s the greatest country on earth.”

Rubio was speaking from inside the gates of the Canyon Gate Country Club. From his podium, he could look out to the perfectly manicured and well-watered golf course. Red tile-roofed McMansions were sprinkled all around and, off in the distance, rose the mountains of Red Rock Canyon.

It was a heady scene for a candidate who, as he told this crowd, spent part of his childhood in a different Las Vegas. His mother cleaned rooms at the old Imperial Palace and his father tended bar at Sam’s Town, a low-end casino off the Strip.

“For me, the journey from behind that bar to the life I live today — that is the essence of the American Dream,” Rubio said. “That journey is what makes America different and special, and it also is what unifies us.”

When Rubio opened up the room for questions, the first came from a man in the back.

“Mr. President,” he began.

The crowd laughed, and Rubio corrected him.

“Marco,” he said, “for now.”