This story was originally published in the October 16 edition of CNN's Meanwhile in America , the daily email about US politics for global readers. Sign up here to receive it every weekday morning.

(CNN) President Donald Trump's ears must have been burning as Democrats met in Ohio at the most crowded presidential debate in US history on Tuesday.

The 12 candidates at the CNN/New York Times debate conjured up visions of a vastly different America should they evict him from the White House in 2020. They'd reverse Trump's erratic, "America First" twists and turns, and restore the US leadership in the world -- somehow. But as the heated exchanges on health care, tax and billionaires showed, the Democratic Party still doesn't know how far left it wants to go.

Who won and lost a debate often takes a few days to become clear as viral moments ignite on social media and voters chew over the post-game analysis. But the early money suggests that this debate will not shake up the wider shape of the race. Former Vice President Joe Biden is a wobbly front runner. Elizabeth Warren has joined him in the top tier (and attacks that she faced on Tuesday night -- the most withering of her career -- show that the rest of the field knows it.)

While some outsiders did well -- like 30-something Pete Buttigieg and centrist Senator Amy Klobuchar, who brought sharp knives for Warren -- everyone else is still struggling to get a look in.

Four takeaways that will shape the campaign

The shadow of impeachment

Joe Biden, reaching for gravitas, said Trump's presidency was "the most corrupt in modern history and all of our history." Kamala Harris said the President had "committed crimes in plain sight." Elizabeth Warren said this was "bigger than politics." Whatever happens with the impeachment inquiry into Donald Trump will tear America even further apart. And if one of the men or women on stage beats him at the polls, they'll end up with the job of trying to put it back together.

What about the Kurds?

All of the candidates agreed Trump was wrong to abruptly remove US troops from the side of Kurdish allies in Syria. But there was a strong isolationist strain onstage, in keeping with the mood of a nation exhausted by foreign wars. Co-frontrunner Warren did not quarrel with Trump's instinct to bring troops home, just with how he's doing it. "I think we want to get out of the Middle East. I do think we should do it responsibly," she said. Until further notice, that is America's message to the rest of the world.

So that's what it's like to be a front-runner

Elizabeth Warren now knows what it's like to have a target on her back. Her rise to effective co-front-runner status exposed her to attacks from all sides on Tuesday. Both Buttigieg and Klobuchar piled on -- seeking to grab the middle ground of many Democrats who fear Warren and Sanders are too left wing. "The difference between a plan and a pipedream is something you can actually get done," said Klobuchar, desperate for a viral moment as she struggles to reach polling thresholds to get her into the next debate.

In one of the most electric moments of the campaign, Biden and Warren -- the two most likely nominees -- clashed directly for the first time.

What heart attack?

Those two stents inserted into one of Bernie Sanders' arteries did the trick. The Vermont senator was "feeling great" and keen to wrest the debate away from Trump-bashing and back to his wheelhouse: health care, student debt and getting rid of billionaires. Sanders supporters will be relieved. But millions of moderate Americans watching at home might be more concerned at his frank admission that taxes will go up to pay for his ambitious social reforms.

Shameful. Shameful!

That was Biden letting off steam at Trump's decision to let Syria roll into northeastern Syria at the expense of America's Kurdish allies. The former vice president has much to vent about the President.

Brexit interlude

There's a generally held view of the European Union as an 11th hour decision-maker, working its way out of difficulties with late-night summits fueled by dozens of cups of coffee and pastries, and prime ministers and presidents only staggering out after midnight to announce a breakthrough.

Sometimes that really is what happens (it's also not uncommon for heads of state convening in Brussels to nip out for frites and a beer during negotiating breaks) but that's not how the EU likes to do things.

In fact, the European Council prefers to have its agenda set two weeks ahead of each summit. That gives the Commission -- its executive body -- time to analyze everything and make recommendations to member states, who also have to prepare. But Brexit is no ordinary agenda item.

This month, the EU has blown through one self-imposed deadline after another, as they try to settle the conditions of a UK exit from the union, before heads of government start turning up in Brussels. On Tuesday, they missed another deadline. As things stand now, no one will have time to digest any Brexit deal before the Thursday summit -- which could mean more stale pastries, fries and head-scratching in the middle of the night, instead.

-- CNN's Richard Greene , writing to Meanwhile

Who said it? Debate edition

"I don't need lessons from you on courage — political or personal."

"That is dead wrong."

"It didn't work in 2016 and it will be a disaster for us in 2020."

"The mainstream media, who have been championing and cheerleading this regime-change war."

"You got the disastrous war in Iraq done."

"MATH"

What good is a 12-person debate anyway?

Glad you asked.

The US electoral map is so vast that most Americans only see presidential candidates on TV, so these events are necessary for Democratic officials to build enthusiasm among voters, reaching tens of millions of viewers -- and not just Democrats. And the crowded field offers more than a soundbite fest — it fleshes out a broader divide between liberal and moderate positions that grassroots voters must adjudicate before choosing a candidate.

There is something quintessentially American about opening the White House race to everyone. The last two US presidents have been a rookie senator from Illinois and a businessman from New York with almost no political experience between them and little in common. Debates are part of a process that must be sufficiently elastic to accommodate sharp shifts in public opinion over a four year cycle.

In a populist age, party elites fear charges of dictating voters' choices, and the field will narrow soon enough anyway. When it does, the debates will have been good practice for the eventual Democratic nominee, who must debate Donald Trump a year from now. Whether they're the right way to pick a decent president is a whole other ballgame.