When Sen. Sherrod Brown Sherrod Campbell BrownHarris faces pivotal moment with Supreme Court battle Remote work poses state tax challenges Senate Democrats release report alleging Trump admin undermined fair housing policies MORE sent a note to supporters this week telling them he was “considering running for president,” he was laying down a marker for the 2020 presidential race.

It was also a message to the dozens of other candidates mulling whether to enter what is likely to be one of the most crowded Democratic presidential primaries in history.

“It’s essentially him marking his turf while he tests the waters,” said one political strategist who has worked on several presidential campaigns. “Make no mistake about it, it’s as much for his rivals as it is for his supporters.”

ADVERTISEMENT

Timing is everything when it comes to a presidential election launch.

Candidates don’t want to announce too soon and they certainly don't want to be the last one to declare — particularly in a field that is expected to near 30 candidates.

During the last presidential cycle, Hillary Clinton Hillary Diane Rodham ClintonDemocratic groups using Bloomberg money to launch M in Spanish language ads in Florida The Hill's Campaign Report: Presidential polls tighten weeks out from Election Day More than 50 Latino faith leaders endorse Biden MORE waited until April of 2015 to announce her candidacy, even as some advisors sought to convince her to announce sooner.

Sen. Bernie Sanders Bernie SandersOutrage erupts over Breonna Taylor grand jury ruling Dimon: Wealth tax 'almost impossible to do' Grand jury charges no officers in Breonna Taylor death MORE, (I-Vt.) announced several weeks later.

On the Republican side, candidates like Jeb Bush announced exploratory runs as early as December in 2014. Donald Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE famously announced his bid at Trump Tower in June of 2015. He was one of the final big candidates to enter the race, and few at the time saw the freight train he would become.

This cycle, only one candidate, Rep. John Delaney John DelaneyCoronavirus Report: The Hill's Steve Clemons interviews Rep. Rodney Davis Eurasia Group founder Ian Bremmer says Trump right on China but wrong on WHO; CDC issues new guidance for large gatherings The Hill's Coronavirus Report: Kansas City Mayor Quinton Lucas says country needs to rethink what 'policing' means; US cases surpass 2 million with no end to pandemic in sight MORE (Md.) has officially declared his candidacy. He’s already spending much of his time in Iowa.

Other potential candidates including Sens. Kamala Harris Kamala HarrisHarris faces pivotal moment with Supreme Court battle Nearly 40 Democratic senators call for climate change questions in debates Joe Biden has long forgotten North Carolina: Today's visit is too late MORE (Calif.) and Cory Booker Cory Anthony BookerBipartisan praise pours in after Ginsburg's death DHS opens probe into allegations at Georgia ICE facility Democratic lawmakers call for an investigation into allegations of medical neglect at Georgia ICE facility MORE (N.J.) have played coy while former Vice President Joe Biden Joe BidenBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Democratic groups using Bloomberg money to launch M in Spanish language ads in Florida Harris faces pivotal moment with Supreme Court battle MORE has said that he will decide whether to run by the end of the year.

Democratic strategist Chris Kofinis, who worked on the presidential campaigns of Wesley Clark and John Edwards, cautioned candidates on declaring too early.

“Avoid before new year, as that is a dead time and you can never redo your launch,” Kofinis said.

He predicted that given the size of the field, voters will see a string of exploratory announcements and formal announcements between the new year and April.

But Democratic strategist Brad Bannon said the front-loaded nature of the 2020 primaries means it’s “the earlier the better.”

“There are dozens of potential candidates and the size of the field dictates the calendar,” Bannon said. “Candidates could get lost in the shuffle if they don’t stake their claims early.

“The candidates are like the Sooners. Thousands of them lined up on the Texas border on the day the Oklahoma territory was opened to settlement. Their motto was the sooner you get there, the more fertile farmland you get,” Bannon said. “So the sooner you start, the better off the candidates will be . . . The latecomers eat dirt.”

Democratic strategist David Wade, who served as a senior aide to 2004 Democratic presidential nominee John Kerry John Forbes KerryThe Memo: Warning signs flash for Trump on debates Divided country, divided church TV ads favored Biden 2-1 in past month MORE, also expects to see candidates begin to announce in the coming weeks.

“There’s a window between Thanksgiving and New Year’s which will define much of the field,” Wade said. “You want to get out front, line up commitments from donors, and lock down staff and activists ahead of the competition, period.

“Unromantic as it is, it isn’t a decision to overthink or overproduce, it’s a decision about ruthless efficiency,” he said.

The only would-be candidates who have the luxury of waiting are the better-known candidates like Biden and Michael Bloomberg. For everyone else, Wade added, “it’s a rush to get out there.”

In his letter to supporters on Tuesday evening, Brown said he was reading comments from supporters on Facebook and Twitter and in private messages. “What an honor to be part of that conversation,” he said. “When people like you stand together and fight for our friends, family, neighbors and communities, we make change a reality. That’s why it’s so important that I hear your opinion about 2020. If you can, let us know your thoughts now.”

Kofinis said that if Biden does announce early or another candidate suddenly catches fire, “then it may lead to a flood of announcements.”

He also said potential candidates will also plan to announce candidacies at the beginning of a quarter to maximize their fundraising.

But as Democrats enter unchartered territory with a large field, Kofinis said that “the nature of this race will upend the rules because we have not had a race like this since the mid 1980s or 1992, where there were so many viable candidates and no overwhelming front runner.”

“Expect the unexpected,” he said.