Presenting the 2020 Democratic bracket

With Vice President Biden's entry this week, there are more than 20 Democratic presidential candidates. Only a handful will be serious contenders when Iowa and New Hampshire voters go to the polls early next year.

To sort out how it might evolve, a good model is the  college basketball tournament — divide aspirants into the following brackets or lanes with the underlying rationale for each:

The governing lane. As well as defeating Donald TrumpDonald John TrumpNASA exec leading moon mission quits weeks after appointment The Hill's Morning Report — After contentious week, Trump heads for Japan Frustration boils over with Senate's 'legislative graveyard' MORE, it's also critical to elect someone with executive experience who can get things done.

ADVERTISEMENT

The Vice president, with eight years serving with Barack ObamaBarack Hussein ObamaAssange hit with 17 new charges, including Espionage Act violations Progressive commentator says Obama was delusional thinking he could work with Republicans Obama makes surprise visit to Washington Nationals youth baseball program MORE and an extensive background as a Senator, is the best credentialed and the heavy favorite in this bracket. If he falters, as the 76-year-old political veteran did in two previous presidential runs, possible beneficiaries might be Governors: former Colorado chief executive John HickenlooperJohn Wright HickenlooperThe Hill's Morning Report - Trump says no legislation until Dems end probes Budowsky: 3 big dangers for Democrats Biden retains large lead over Sanders, other 2020 Dems in new Hill-HarrisX poll MORE or Washington state's Jay InsleeJay Robert InsleeOvernight Energy: Democrats ask if EPA chief misled on vehicle emissions | Dem senators want NBC debate focused on climate change | 2020 hopeful John Delaney unveils T climate plan 2020 Democrats join striking McDonald's workers Democratic senators want NBC primary debate to focus on climate change MORE.

Others who could fill this void, if they got in, would be two successful mayors: Mitch Landrieu of New Orleans or New York's Michael Bloomberg. The hour probably is too late.

The left lane. Much of the energy in the party is on the left, their champion is Bernie SandersBernie Sanders2020 Democrats join striking McDonald's workers Billionaire's M gift to Morehouse grads points way to student debt solution Poll: Nearly half of Clinton's former supporters back Biden MORE. The Vermont Senator runs strongly in the polls, along with Biden, well ahead of the pack at this early stage, and in grass roots fund-raising.

The prospect of the 77-year-old Socialist as the nominee, or even setting the agenda, terrifies mainstream Democrats.

The only alternative in a bracket that will make the Democrats' Final Four is Massachusetts Sen. Elizabeth WarrenElizabeth Ann WarrenThe Hill's Morning Report — After contentious week, Trump heads for Japan On The Money: Senate passes disaster aid bill after deal with Trump | Trump to offer B aid package for farmers | House votes to boost retirement savings | Study says new tariffs to double costs for consumers Overnight Energy: Democrats ask if EPA chief misled on vehicle emissions | Dem senators want NBC debate focused on climate change | 2020 hopeful John Delaney unveils T climate plan MORE, a decidedly liberal capitalist. She has offered some thoughtful policy proposals, as well as a lurch or two to the fringe left, but so far just hasn't caught on. There’s still time; when it gets down to choosing time, there's not room for both her and Sanders.

The generational lane. With pervasive cynicism about the ways of Washington, it's time to move beyond the baby boomers, and there are three attractive alternatives: 46-year-old Beto O'RourkeBeto O'RourkeButtiegieg backs NFL players' right to protest during anthem: I 'put my life on the line to defend' that Overnight Energy: Democrats ask if EPA chief misled on vehicle emissions | Dem senators want NBC debate focused on climate change | 2020 hopeful John Delaney unveils T climate plan CNN's O'Rourke town hall finishes behind Fox News, MSNBC MORE who dazzled Democrats around the country when he came close to right wing Texas Sen. Ted CruzRafael (Ted) Edward CruzThe Hill's Morning Report — After contentious week, Trump heads for Japan Senate GOP votes to permanently ban earmarks Jim Carrey fires back at 'Joe McCarthy wanna-be' Cruz MORE last fall; Pete ButtigiegPeter (Pete) Paul ButtigiegButtiegieg backs NFL players' right to protest during anthem: I 'put my life on the line to defend' that 2020 Democrats join striking McDonald's workers Poll: Nearly half of Clinton's former supporters back Biden MORE, the 37-year-old Mayor of South Bend, Indiana, a former Rhodes scholar who was deployed as a Naval Intelligence officer in Afghanistan; and Massachusetts Congressman Seth MoultonSeth Wilbur MoultonRepublicans attempt to amend retirement savings bill to include anti-BDS language CNN's O'Rourke town hall finishes behind Fox News, MSNBC Pelosi employs committee chairs to tamp down calls for Trump impeachment MORE, a Harvard graduate and Marine who served four tours in Iraq.

ADVERTISEMENT

A year ago most of the chatter would have focused on Moulton, who made a big splash when he arrived in Congress and enlisted some of the young veterans who unseated Republican congressmen last November, but he took a hit with his clumsy effort in opposing Nancy PelosiNancy PelosiThe Hill's Morning Report — After contentious week, Trump heads for Japan Frustration boils over with Senate's 'legislative graveyard' Trump-Pelosi fight threatens drug pricing talks MORE as Speaker, supporting instead an undistinguished Ohio Congresswoman, Marsha Fudge.

O'Rourke, only a month ago, generated much excitement among the rank and file, particularly young voters. That has given way to Buttigieg, seen as the “authentic Beto.” We'll soon see if the young mayor of a town of 102,000 can take the big league heat or if either of other two can restart.

The diversity lane. Barack Obama, still the most popular political figure in the country, broke the mold becoming the first African-American President; people of color are the party's base. There are three substantive candidates: California Sen. Kamala HarrisKamala Devi HarrisCastro swears off donations from oil, gas, coal executives Harris leads California Democrats in condemning HUD immigrant housing policy Billionaire's M gift to Morehouse grads points way to student debt solution MORE, New Jersey Sen. Corey Booker, and former Housing Secretary Julian CastroJulian CastroDe Blasio pitches himself as tough New Yorker who can take on 'Don the con' Michael Bennet must find a way to stand out in the crowd Sandra Bland's sister: She's 'literally speaking for herself even beyond her grave' in video MORE of Texas.

Booker so far hasn't lived up to his anticipated potential and is seeking to reignite his campaign. Harris has the most natural path to the nomination if she improves as a candidate with a more coherent message and avoids the sort of mistakes she has made.

It's exceedingly difficult to see a path for most others. Perhaps someone like Minnesota Sen. Amy Klobuchar will have a moment as Howard Dean did in 2004. But it's hard to see how that's sustainable.

In the snows of January, as voting starts, there probably will be one, perhaps two (though that's remote), from these brackets. There won't be enough oxygen for the others.

This is a scenario with a caveat: Four years ago, on the Republican side, Donald Trump didn't fit into any conventional political lane.

He still doesn't.

Albert R. Hunt is the former executive editor of Bloomberg News. He previously served as reporter, bureau chief and Washington editor for the Wall Street Journal. For almost a quarter century he wrote a column on politics for The Wall Street Journal, then the International New York Times and Bloomberg View. Follow him on Twitter @alhuntdc.