The midterms aren't entirely over -- there are still key undecided contests -- but the 2020 race is already underway. Three little known candidates have declared, and as many as 38 others are considering a run or are speculative candidates for the Democratic nomination, including three billionaires: Michael Bloomberg, Howard Schultz, and Tom Steyer (see chart at bottom). A fourth billionaire, Mark Cuban, has expressed interest in an independent bid. Should a billionaire prevail in the Democratic primary and Trump run for reelection, Americans could be looking at a three-way billionaire presidential ballot in the 2020 general election.

So who out of the Democratic billionaires has the best chance? For my money, it's Tom Steyer. The hedge fund manager spent the last year building Need to Impeach, "an organization with more reach than the NRA," with more than six million supporters. While many Beltway Democrats think the effort is harmful to party messaging, they often don't understand the scope of the operation. NTI has not only tapped into liberal anger over an illegitimate presidency, but it has thereby created a voter engagement and mobilization juggernaut independent of the Democratic Party. Steyer put $120 million into the midterms to elect Democrats, flip the House, and put a check on Trump. Kevin Mack, a DC veteran who is Steyer's chief political strategist, told CNBC that Need to Impeach "won at least 70 percent of its targeted races [in the 2018 midterms] and that could grow to 76 percent when all of the ballots are counted." That's a lot of chits.

Steyer's signature issue, even more so than impeachment, is climate change. Before Need to Impeach, in 2013, he built NextGen America to advocate for the transition to a clean energy economy, and it has a significant presence in swing states. His position on the environment stands in stark contrast to that of Trump, who is decimating the EPA and trying to revive the coal industry. Increasingly extreme weather events linked to climate change across the country and increasingly dire predictions from the scientific community -- Trump's own administration is predicting a seven degree rise in temperature by 2100 -- could culminate in 2020 being the election where climate change finally becomes a marquee issue. Steyer also supports universal health care, immigrant rights, raising the minimum wage to $15 an hour, and overturning Citizens United, all major progressive legislative priorities. He can both credibly claim the mantle of progressive, and that of an outsider willing to buck the establishment. (Full disclosure: my web-show, The Undercurrent, has collaborated with Need to Impeach on field reporting videos.)

The other two billionaires considering Democratic bids are centrists, one of whom, Michael Bloomberg, registered as a Democrat only last month. Bloomberg has a long history of party hopping: he was a Democrat prior to 2001, when he became a Republican to run for mayor of New York City, and in 2007, he registered as an independent. The business tycoon plowed $110 million into the midterms to elect Democrats, so he's also got his chits in the party. However, many of his values are way out of whack, notwithstanding his efforts on gun reform and climate change.

Bloomberg made his money on Wall Street, first as a partner in the Salomon Brothers investment bank, and later starting his own company to provide business information to financial firms. He was a harsh critic of the Dodd Frank financial reform bill signed into law in the wake of the 2008 financial crisis. In 2012, he supported Republican Scott Brown in his Senate race against progressive favorite Elizabeth Warren, denouncing her Wall Street reform philosophy as Soviet-style communism. But many, myself included, argue today that anger against Democrats for not holding the Big Banks more accountable helped to propel Trump to the presidency. Polling from late May shows that voters "overwhelmingly" want to reduce Wall Street's influence on Washington.

As the mayor of New York, Bloomberg controversially increased the minority-targeting law enforcement practice of "stop and frisk" by over 500%. He had bad relations with the city's unions, who are stalwart Democratic allies: he compared the teachers' union to the NRA; fought the New York Transit Authority, leading to strikes; and left office with 152 unresolved labor contracts. He supports cutting Social Security and Medicare to rein in the deficit, anathema not just to the Democratic base, but to a majority of the electorate. On top of all of that, Bloomberg is derided by liberals and conservatives alike for imposing "nanny state" bans on large sodas, tobacco, trans fats, and more.

We have the least political information on centrist Starbucks billionaire Howard Schultz, since he has neither been a politician nor activist for as long as Bloomberg and Steyer. It's not clear whether Schultz is actually a Democrat -- Politico reported that in January that he would likely run as an independent, while other outlets since have pegged him for a Democratic candidacy. He just hired Steve Schmidt, a former Republican operative who managed John McCain's 2008 presidential campaign, as a key player on his PR team. Schmidt left the Republican Party earlier this year over his disdain for Trump, but what Democrat hires former Republicans as campaign advisers? Schmidt's hiring doesn't exactly augur significant overtures to the progressive wing of the party, and for Democrats to win against Trump, the nominee must motivate the base.

In 2011, Schultz hosted a town hall for No Labels, a nonpartisan group that supports moderates of both parties, and in 2016, he endorsed Hillary Clinton. He is a donor mainly to Democrats. Last summer in an interview with CNBC, Schultz criticized Democrats for "veering too far left" on single-payer health care, which now has the support of 70% of Americans and 85% of Democrats, according to polling from August. He also called for cutting Social Security and Medicare benefits in order to tackle the national debt, two programs which as aforementioned, are vastly popular with the electorate.

So in the billionaire lane of 2020 Democratic contenders, Steyer wins. He's the only real Democrat. He's the only one aligned with the values of the ascendant progressive wing of the Democratic Party, and who still has deep and independent relationships to the party establishment. He's built his own campaign infrastructure, that is engaging voters and expanding the electorate. He can speak credibly as an outsider; offer a positive, progressive vision for America; and draw clear contrasts with Trump.

However, all of these men have practically unlimited resources to self-finance their campaigns through to the end of the primary if they wish to do so. While money is no guarantee of popular support, it will certainly have a huge impact on the dynamics of the race for the traditional candidates who will have to scramble for cash in an unwieldy field.