Julian Castro 2014
CNN  — 

Mark it down: On December 12, 2018, a mere 629 days before the 2020 general election, the Democratic race to unseat President Donald Trump began.

And it began fittingly, given the current occupant of the White House, with a tweet:

“As a kid growing up on the west side of San Antonio, I never thought that I’d one day be making this announcement: http://www.julianforthefuture.com I’m exploring a candidacy for President of the United States in 2020 to renew the promise of this country for all.”

That’s Julian Castro, the former mayor of San Antonio and head of the department of Housing and Urban Development in the Obama administration. And with that tweet – and Castro’s tease that he will make a formal announcement of his future plans on January 12 – we now have the first serious contender for the Democratic presidential nomination in the race.

(Nota bene: Sorry John Delaney. Yes, you have been running for president for a while now. And you seem great! But it’s hard to see a path for you to be the nominee. Ditto to Richard Ojeda.)

Castro, just in case you are really bad at reading between the lines, is going to run.

“I’m definitely leaning in one direction in terms of my candidacy for president,” he told CNN. Um, no kidding.

It’s too early, you will shout! The last election isn’t even totally over, you will yell! (Trust me: People yell this at me all the time. Literally.)

But, here’s the thing: It’s not too early. Not at all.

Imagine you are Castro. Six years ago – when you delivered the keynote address at the 2012 Democratic National Convention – you were the hottest thing going in Democratic politics. Then you were a leading candidate to be Hillary Clinton’s vice president in 2016.

Now, though, there is a new, young inspirational Democrat from Texas: Beto O’Rourke. And O’Rourke is thinking about running, meeting with the likes of Barack Obama and Andrew Gillum to semi-publicly mull the race.

Castro can’t afford to wait until O’Rourke makes his mind up. Literally. If O’Rourke gets in the race, lots and lots of the Texas money men and women that Castro needs to raise the kind of cash to make himself a viable candidate will flock to Beto. At which point, Castro’s campaign would be over before it even started.

Getting out in front of O’Rourke – and everyone else this side of Delaney – then, is Castro’s best chance to make a real run at the presidential nomination. The longer he waited, the more crowded the field would get. The harder to distinguish yourself to voters in early states like Iowa and New Hampshire. The tougher competition for the most sought-after political operatives. And on and on and on.

The reality of running for president is best understood by thinking of it as an iceberg. The very small part that most people see above the surface comes in January and February 2020, when people actually vote in primaries or caucuses. The piece under the surface – that few people outside of politics and media see – is not only larger than the tip of the iceberg (ahem) but also much more important.

The goal of anyone – and there could be as many (or more) than 30 “anyones” in the 2020 Democratic race – running for president is to put the structural piece (organization, money etc.) in place that if they happen to catch the imagination of the primary electorate at the right moment, they have the ability to fully capitalize.

That takes time. Lots and lots of time.

So, no, Castro isn’t starting this 2020 race too early. This race has been going on behind the scenes for Democrats since the day Donald Trump beat Hillary Clinton in 2016. He’s just the first (potentially) major candidate to all but admit the obvious: He’s running.