Des Moines, Iowa (CNN) Democrats who are considering running for president -- but who don't have names like Biden, Warren or Sanders -- will enter early 2019 facing question about their ability to break through in a crowded field of potential 2020 candidates.

Three of these possible candidates -- Democratic Sen. Jeff Merkley, Rep. Eric Swalwell and South Bend, Indiana, Mayor Pete Buttigieg -- spoke at Progress Iowa's holiday party in Des Moines on Thursday, getting critical face time with activists in the state ahead of what is expected to be a large field of candidates vying for the Democratic nomination.

These three are far less known than other possible contenders like former Vice President Joe Biden or Massachusetts Sen. Elizabeth Warren, meaning they will enter 2019 staring up at a mountain as they try to determine whether they can cobble together enough support, money and energy to break through.

"It's daunting," Swalwell told CNN. "But I really believe there has to be a go big, be bold candidate who represents the next generation in the field."

Swalwell, who said he will take the holiday spent with his wife's family in Indiana to consider a presidential bid, added that one of his biggest concerns is whether he can run a campaign that is real and not just about raising his own profile.

"I don't want to do it half-assed," he said. "I would want it to be a serious campaign that could be a winning campaign."

Buttigieg, who recently announced he will not seek a third term as mayor, told CNN that he expects to make a decision on running in the next few weeks, in part because of the challenges faced by lesser known candidates like himself.

"I think any candidate that is not already very famous probably needs to make some kind of move in January," said Buttigieg, who added that he is actually invigorated by entering the race with few expectations.

"A field that is spread very thin probably works to the advantage of a newcomer if you are very good at it, and the only way to find out is to be tested in the field," he said.

Even with that confidence, though, past presidential cycles, namely the Republican primary in 2016, showed how difficult it can be to move from the lower rungs of candidates into the upper echelons.

One reason has historically been debates, especially since candidates have previously been ranked by their collective place in polls and separated by primetime debates and what pejoratively came to be known as the "kiddie table" debates. The Democratic National Committee announced on Thursday that they will try to avoid that scenario at least for the first two debates of 2019 by randomly splitting up candidates if there is a large field and holding debates on consecutive nights.

Lesser-known candidates will face a set of challenges that won't impact higher-profile challengers who have national name recognition, aides lined up to work for them and campaigns-in-waiting anticipating their orders. Can they cobble together enough money to hire staff a barebones campaign? Will they get enough face time with grassroots organizers in Iowa and New Hampshire to get them behind their story and message? And will there be enough media attention to go around in a field of two dozen that includes a slew of heavy hitters?

And conversations with top operatives in Iowa and New Hampshire indicate that party insiders expect a very difficult road ahead for second and third tier candidates in 2020, primarily because of how many big-name Democrats are considering a run.

"This year is going to be more challenging for second tier candidates than I have ever seen," said Jim Demers, the New Hampshire operative who helped introduce then Sen. Barack Obama to the state in 2008s. "It would be one thing if there are one or two big names, but there are like 7, so that makes it much more difficult for any of the lesser candidates to get any traction whatsoever."

Demers, who is backing New Jersey Sen. Cory Booker's possible run, says one key issue facing lesser known Democrats is the ability to stay in the news and drive support and donations with media attention.

"There are so many candidates looking at running and they all have to figure out how they get access to three things that will be limited: Votes, money, media," said Demers. "Big names, little names, they are all going to be competing for the same attention in these states."

Matt Paul, Hillary Clinton's Iowa state director in 2016 and a longtime operative in the state, said one way to combat that is by showing up early, when there is more space for each candidate.

"They need some oxygen to boost their campaign right away," said Paul, a Democrat who has helped introduce possible candidates like Montana Gov. Steve Bullock and former New York Mayor Michael Bloomberg around Iowa. "As there is all of this attention on why might run, who might get in, it's a good opportunity to sneak in and do some of the organizing."

But since the 2018 midterms, trips to Iowa have been scarce. Many possible 2020 contenders traveled to Iowa and New Hampshire ahead of the midterms under the pretense that they were campaigning for local elected. But few continued those trips since Democratic victories in November, a fact that has surprised many because of the way success in early states can come to unexpected candidates.

Rep. John Delaney is not one of those Democrats, however. The Maryland businessman announced his candidacy in July 2017 and has been campaigning for nearly 17 months -- making a whopping 20 trips to Iowa.

One reason, Delaney said, is he wanted media attention when no other candidates were in.

"The coverage in the media you can basically translate into dollars," he said. "I have to spend a certain amount of money to get my TV, but enough coverage in the media equates to ad dollars."

Unlike well-known candidates, Delaney said, "we have to go to Iowa and go to New Hampshire and we have to drive around and do meet-and-greets and impress people on a personal level."

To date, the strategy hasn't caught on: CNN's most recent poll had Delaney as 1% of Iowans first choice with 64% of Iowa Democrats "not sure" about their opinion of the Maryland Democrat.

Delaney is undeterred, however, in part because top operatives working for lesser known Democrats believe at least some lower lever candidates will over perform by being the right candidate at the right time.

The thinking goes like this: Although attention will be difficult to come by, every candidate will get their time in the spotlight and what they do with that moment will determine whether they vault into the top tier or fizzle.

"It's luck, it's timing, it's place," said a source close to Merkley. "Almost every nominee in modern American history has had to have two things going for them: One they have had to have a clear and coherent message and strategy that breaks through and then the other thing is circumstance."