Which three runners will drape themselves in the American flag at the finish line of the 2016 Trials? At this point, it’s impossible to guess.

So, are you an optimist or a pessimist?

Do you look at the state of elite-level men’s marathoning in the U.S. and get excited? Or is the view depressing?

Today we’re exactly 18 months away from the 2016 U.S. Olympic Trials Marathon races in Los Angeles. Three Olympic team slots are up for grabs and you could argue there isn’t a single runner in the driver’s seat at this point to grab one.

Is that thrilling or terrifying? Because there are two ways to look at it, depending on how full (or empty) your glass is:

— The field is wide open, and that’s great. While the well-known veterans—Meb Keflezighi, Ryan Hall, Dathan Ritzenhein, Abdi Abdirahman—are still forces to be reckoned with, there are so many marathoners in the 2:10-2:12 range today that the trials are going to have unmatched intrigue. Plus, the recent retirement announcements from Jason Hartman and Andrew Carlson could open up a chance for other up-and-coming runners. There are no less than a dozen runners with a legitimate chance at contending for one of those three slots.

— On the flip side, one could make the argument that American competitiveness will end there. Everyone in the field has flaws: Keflezighi, 39, and Abdirahman, 37, aren’t getting any younger, Ritzenhein, 31, continues to struggle with injuries and Hall isn’t the runner he was even two years ago. Not to mention the fact that no other current American runner, so far, has broken 2:10. The warts are real, and there may be enough of them to prevent anyone in the U.S. from being consistently competitive on the world’s stage in the next few years.

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The mystery of the 2016 trials should be fun to watch play out, but some say the bigger picture isn’t a rosy one.

“We’re just not that good in the marathon,” says Greg McMillan, a running coach who trained pros through adidas-sponsored McMillan Elite team for several years. “When you look at the list, we only have nine U.S. citizens that have broken 2:10 on non-aided courses [four who are currently running], and only six more on aided courses like Boston. That’s pretty bad. In other countries, they’ll have that many (break 2:10) in a weekend.”

Why can’t the U.S. be more competitive? We live in a sports-crazed country of 300 million people. It has the technology and the resources for cutting-edge training like the Nike Oregon Project. It has the geography for altitude training. And the latest running boom over the last 10 years has drawn more interest to the sport than ever before, both at the entry level and at the competitive level.

Yet when Ryan Hall leaned across the finish line at the 2008 London Marathon in 2:06:17, it represented a high-water mark of sorts (Keflezighi’s major victories aside). No American has come within 90 seconds of Hall’s performance that day on an unaided course—not even Hall himself. And really, nobody seems poised to anytime soon.

To take it one step further, as of Aug. 13, there are 60 runners from around the world who have run faster this year than Meb Keflezighi’s Boston Marathon-winning time of 2:08:37. Not only are there no Americans among the top 60, but Hall, Ritzenhein and Khalid Khannouchi are the only U.S. runners to have ever run that fast.

So while the trials will be a must-see event and will serve as a quadrennial benchmark of American distance running, the drama could very well end there. And everybody has a theory as to why U.S. runners struggle to stack up alongside other countries in the marathon.

RELATED: Chasing The American Dream From Oslo

Starting Young

Lifting the flag of Uganda over his head with a huge grin stretching across his face, Stephen Kiprotich crossed the finish line of the 2012 Olympic marathon in a winning time of 2:08:01.

Kiprotich was 23 years old that day. It was his fourth marathon.

Such experience at such a young age is nearly unheard of in the U.S. Heck, many 23-year-olds in the U.S. are still running college track. Even Hall, who started running the distance earlier than most Americans, made his marathon debut at the age of 24.

While Keflezighi has shown that a marathoner can be successful well into his 30s, many think the younger years are where the foundation is most effectively set.

“The Ethiopians and the Kenyans, these are guys who are running marathons young. They’re running marathons at 21, 22, 23,” says Pete Rea, who coaches a team of elite athletes at Reebok-sponsored ZAP Fitness. “They’re honing it, they’re mastering it, they’re learning the subtleties associated with the marathon.”

Many elite American runners, though, take a slower path. They finish college at 22 or 23, head straight to track, and, depending on their rate of success, move to road races and marathons sometime after that.

“A lot of the African athletes are jumping into the marathon at 19, 20 years old,” says Sam Grotewold, manager of professional athletes for the New York Road Runners. “But in the U.S., people tend to wait longer. That’s the way it’s always gone.”

The Cost of Progression

Ryan Vail is encouraged by his marathon career so far. Save his 2:13 finish at the 2013 New York City Marathon, he’s been able to progress at each of his races—a 2:12 at the Olympic Trials in 2012, a 2:11 at the Fukuoka Marathon later that year, and a 2:10 at the London Marathon this past April.

“I still feel like I have a few minutes to go,” says Vail, 28, who lives in Portland, Ore. “It’s one step at a time. I’m now a 2:10 guy, so I’m going to start looking at 2:09. When you hit 2:09, you can start talking about 2:08.”

Vail readily admits he doesn’t have the natural talent of a fast track guy like Ritzenhein, who’s marathon PR is 2:07:47, so a slow and steady progression like this is his ticket.

“Is 2:07 out of reach?” Vail says. “I hope not. But it’s going to take time to get there.”

It’s time that some runners can’t afford to take—literally.

Jeffrey Eggleston, who lowered his PR to 2:10:52 at the Gold Coast Marathon in Australia this summer, compares professional marathon running to any other career where you have to work your way up—and struggle financially at first.

“You have to pay your dues, and you need to invest in yourself,” says Eggleston, 29, who trains in Boulder, Colo.. “You have to build up your running resume and go to different races and make an investment in yourself to keep running at a high level.”

But dropping from, say, a 2:15 personal best to a 2:10 or even lower (which means more money) can be a long process, and the results certainly aren’t guaranteed. Meanwhile, many of these runners have degrees from well-known universities. Starting a career in the real world can be an enticing option for them, and their potential in the marathon could go unrealized as a result.

“The economics for us are very tough,” McMillan says. “Most distance runners have good college degrees and can get good jobs. In other countries, running is the way out. [Running] is the good job.”

He adds: “We lose them all the time. Everyone who ran in college knows of athletes who could’ve developed into really good runners. But they got jobs.”

The Battle With Track

Galen Rupp has become the darling of American distance running, winning silver in the 10,000 meters at the London Olympics and breaking his own American record in the event earlier this year at the Prefontaine Classic. His talent has marathon fans drooling. A 1:00:30 half marathon  in 2011 was another clue at Rupp’s potential brilliance at longer distances.

But if we want to see what Rupp, 28, is capable of doing in the marathon, we’re going to have to wait. His coach, Alberto Salazar, has said it will be after the 2016 Olympics before Rupp even considers making the jump. Rupp will be 30 years old in two years when the Games hit Rio.

Oftentimes, the top few 5,000- and 10,000-meter runners make a good living on the track during their prime speed years, while the next tier find better potential earnings in the marathon and shorter road races. Depth among American distance runners matters. The marathon suffers more than other events when there’s not enough of it.

“If you’re an American who’s a 13:35 5Ker, you can make a living and still stick with the shorter races,” Rea says. “In Kenya, (with that time) you run road races and you run marathons.”

Rupp has run a 12:58 in the 5,000 meters, and his Olymic medal cemented his rockstar status—likely a well-compensated one with his sponsorship backing from Nike. While marathon fans certainly want to see Rupp take on the distance (his training partner, Mo Farah of Great Britain, ran a 2:08 in his marathon debut at London this past April), many close to the sport understand why Rupp is staying on the track for now.

“He has a silver medal and the American record. I’m sure he’s well-compensated. He can do whatever he wants,” McMillan says. “The major marathons would pay him six figures, maybe even seven figures with a multi-year deal. It’s not financial with him. It’s strategy.”

Grotewold figures the marathon will eventually lure in most of America’s top track stars. He looks at runners like Rupp, Chris Derrick and Ben True and sees America’s future in the event—even though they haven’t attempted it yet. Derrick, a two-time U.S. cross country champion, is 23, while True, sixth at the world cross country championships in 2013, is 28.

“For all of them, it’s coming,” Grotewold says. “Maybe not by 2016, but it’s coming. Someone among that group will be a 2:06, 2:07 guy.”

Training Philosophies

The simplified stereotype of U.S. marathon training is its prioritization of volume over intensity. Vail thinks there’s some truth to it.

“There are so many runners doing different things, so it’s hard to speak for everybody,” Vail says. “But I feel like there’s an overemphasis on saying ‘I run this many miles in a week.’ Yeah, but how many are you doing hard?’ I think there’s got to be a balance between those.

“U.S. distance runners are still trying to find that balance.”

Coaches like Rea and McMillan think the Americans are close to nailing it down, with several coaches beginning to do the high-intensity workouts like 30K runs at marathon pace that international runners are already doing.

The difference, McMillan says, is the gains made with those intense workouts are not created equal.

“The problem is the preparation for becoming a runner at the age of 20,” McMillan says. “In some countries, the athletes have 15 years of basic foundational training under their belts just as part of their lifestyle.

“You have a greater aerobic base behind it. If you add intensity on top of it, obviously that athlete is going to have huge improvements. So Americans are behind the 8-ball, but not because the training philosophy doesn’t match what the best runners in the world are doing. It’s because the best runners have a different background.”

Is the Bar Too Low?

Tsegaye Mekonnen, an 18-year-old Ethiopian, won the Dubai Marathon in 2:04:32 earlier this year, pulling away from fellow countrymen Markos Geneti at the 22-mile mark.

It was a remarkable debut, but not just because of that 2:04 time or even the fact that he’s still a teenager. Rather, Mekonnen stayed with the lead pack to run the first half of Dubai in 1:01:27. Before that race, his PR in the half marathon was 1:02:53.

That is a courageous, go-for-it attitude that Eggleston said Americans don’t show enough of—perhaps to their detriment.

“They don’t think about it. They go for it. They’re willing to lay it on the line,” Eggleston says of East Africans like Mekonnen. “Americans are way more conservative. I don’t want to criticize us for that because maybe we’re being smart and running within ourselves. But we never really take a huge risk and stick our neck out.”

Are low expectations holding Americans back? It seems trivial compared to the other, more tangible reasons. But multiple people interviewed for this story cited it as a possible factor.

“2:10 is a very, very good marathon. Exceptional. But at international races, it’s not competitive anymore,” Rea says. “We need to start thinking more along the lines of 2:07, 2:08 as something feasible.”

Eggleston agrees.

“If we want to run 2:08, we should shoot for 2:08,” he says. “I think athletes are trying to get their feet wet in the marathon and are shooting for more modest starting points. If you want to be world class, you’ve got to go for it.”

The Future

The pessimists have plenty of evidence, but optimism will always have its place. While the men’s marathon in the U.S. has a lot of question marks heading into 2016 and beyond, there are runners capable of quieting the skeptics.

Keflezighi, Hall and Ritzenhein are all dangerous, experienced runners despite their question marks. Kelfezighi, despite his age and relatively modest personal best of 2:08:37 set in winning this year’s Boston Marathon, has shown that he can still mix it up in a championship-style race. Eggleston, Vail and Brett Gotcher are 2:10 guys who are still in their 20s, and still improving. There are several more 2:11 guys in the mix—Nick Arciniaga, Fernando Cabada and Andrew Carlson, to name a few.

In addition, several track stars are starting to trickle up to the marathon as well. Rupp is a possibility after 2016 and has the talent to make an immediate impact. Matt Tegenkamp, one of a few American track athletes to break 13 minutes in the 5,000, debuted with a 2:12 at last fall’s Chicago Marathon and told FloTrack afterwards, “I think I can make big strides in this event.” But Tegenkamp is already 32.

The pessimists have a point (many points, actually), but the optimists have a few, too. The next 18 months will see runners strategically choosing races with a build-up to the Olympic Trials in mind. Then, on Feb. 13, 2016 they will battle it out on the streets of Los Angeles.

Which three runners will drape themselves in the American flag at the finish line? At this point, it’s impossible to guess. Whether that’s good or bad, it’s certainly intriguing.

“Could Ryan Hall make another team? Sure. Could Dathan make another team? He could. Meb? Absolutely,” Rea says. “But there are a cadre of young guns waiting in the wings and training hard and one of them could break through—people like Jeff Eggleston and Christo Landry and Tyler Pennel and Craig Leon. I think you’re going to see a couple of guys do some amazing things in 2016 and 2020 and hopefully we start thinking differently about what’s good on an international level.”