There were some significant disagreements among the Democratic presidential candidates on stage in Miami Wednesday night. Reps. Tulsi Gabbard and Tim Ryan clashed on foreign policy. Sens. Elizabeth Warren and Amy Klobuchar quarreled about Medicare-for-All. Former Housing and Urban Development Secretary Julian Castro and former Rep. Beto O'Rourke sparred over details of immigration policy.

But there was a much deeper underlying consensus uniting the candidates. The Democrats are a party of unapologetic earnestness. Its candidates are animated by a powerful impulse to do good — and to appear to be taking a noble stand for What's Right. It was there in Warren's multitude of ambitious plans to fix a million broken things about the country. It was there in the competition between O'Rourke, Castro, and Sen. Cory Booker over who can show greater solidarity with migrants by speaking fluent Spanish. It was there in promises to combat climate change, impeach or prosecute President Trump, and aggressively fight gun violence.

If you incline to the left or center-left, this might sound obvious. Of course people running for president want to use government to do great things for the country. Why go through such immense effort if not to use political power to make a moral difference and elevate themselves in the process?

But this isn't obvious at all. I don't mean to suggest that Republican office holders actively want to hurt the country. The ideology most of them espouse inclines them toward skepticism of government power. That's why their plans often involve the government getting out of the way and doing less (at least in domestic policy) so that individuals, businesses, and markets can contribute to the prosperity and flourishing of all.

That's the Reaganite gospel. But in recent election cycles, this has been joined by something darker — something even further removed from the Democrats' unabashed public-spiritedness. We saw it first in Sarah Palin's proudly ill-informed vice-presidential campaign in 2008. It returned with a vengeance in the GOP primary debates in 2011 and 2012, when the candidates pandered to audiences that booed when a gay soldier asked a question, cheered talk of executions, and yelled viciously in response to a question about a young, uninsured man facing death.

It was this that Donald Trump tapped into and amplified so effectively four years later — by running a campaign that was permeated from top to bottom by anger and contempt. Trump was all derision, all the way down. And two and a half years into his presidency, that hasn't changed one bit.

America's parties are polarized in all sorts of ways — on taxes and regulations, on health care, on immigration, on abortion. But they are also sharply divided in the way they approach public life. The Trumpified Republican Party defines itself by blunt, combative, absolute opposition to everything the left stands for. The Democrats dislike conservatives, too, and disgust at Trump in particular is helping to drive them further left. But their convictions aren't defined by rejection of Republican policy positions.

The candidates on stage Wednesday night have lists upon lists of things they're dying to do and accomplish. These aren't just negations and reversals of Trump policies. They are big, expensive, ambitious plans and programs of their own. Some of the candidates — like Warren, Castro, and Booker — even speak with confident intensity, like true believers on a moral crusade to redeem the world with white papers. Where Trump uses the vocabulary of a grade school bully to express belligerent impulses, the Democrats talk like preachers fresh from seminary who are eager to spread a gospel of government and good intentions. It's all smiles, sweet talk, and righteous indignation eager for redemption.

Seventeen months from now, Americans will be faced with a choice between parties, candidates, and policies. But as one could clearly see in the first debate of the campaign cycle, they will also be choosing between two very different styles of politics and visions of our national future. A president of the purest petulance will be squaring off against an army of the earnest. And we have no way to know which option will hold the greater electoral appeal.