OPINION — Congressional infighting. Internal clashes over policy. Primary threats. A candidate field the size of a small village and a set of party rules that may or may not yield a fair process. The Democrats’ 2020 presidential primary season has officially begun.

It may end up a three-ring circus of unhappy losers and their equally unhappy supporters or an equitable winnowing of one the biggest fields of presidential candidates in modern history. Whether the process works and is seen as fair to all will be crucial to ensuring a party unified behind its eventual nominee. That’s where it gets complicated for the Democrats.

They begin their presidential primary season with less than ideal atmospherics. The Mueller report has yet to deliver. The economy is doing well, while congressional Democrats are becoming more and more publicly divided over both personalities and policies. The Green New Deal, “Medicare-for-all,” the Amazon fiasco, reparations for slavery and support for Israel demonstrate serious policy fractures within the party, whose traditional leaders, Chuck Schumer and Nancy Pelosi, are faced with near ideological revolt from its progressive wing, led by Bernie Sanders and Alexandria Ocasio-Cortez.

Meanwhile, newly elected, more centrist Democrats from purple or even red districts have shown some surprising independence in their first two months, apparently not intimidated by Pelosi’s reputation when it comes to controlling her caucus.

And then, of course, there is the “Squad,” as they call themselves. Reps. AOC, Ayanna Pressley, Rashida Tlaib and Ilhan Omar are threatening Democratic colleagues with primary challenges, sending anti-Semitic tweets and making profane statements that grab headlines and eyeballs — while their leadership fumes.

Flashback: Green New Deal sounds like a ‘high school term paper that got a low mark,’ Trump says

What are presidential candidates, especially those in Congress, to do as they try to straddle this growing divide and round up support in an increasingly crowded field? It’s a dilemma that has driven many of the early candidates to embrace the progressives’ radical agenda, an impulsive decision they may come to regret.

Then there’s the elephant in the room — impeachment. The Democratic base and a significant number of their House majority want nothing less than the impeachment of Donald Trump, who they see as an illegitimate and corrupt president. Frog-marching Trump out of the White House keeps hope alive for their base.

But impeachment, as Republicans learned the hard way in 1998, is a risky business when it comes to general elections. For Maxine Waters and other Trump antagonists to continue to push for what is, at this point, a clearly partisan effort based on their dislike of him personally is a bad idea Democrats may also live to regret.

Beyond party infighting, with the presidential primary getting underway, the most interesting factor is the growing number of Democratic candidates and how the nominating and debate rules for the 2020 election, both new and old, will impact the field.

Last August, the DNC changed its nominating rules to lessen the impact of the so-called superdelegates, which the Sanders campaign complained had rigged the 2016 nomination for Hillary Clinton. The bitterness from that hard-fought campaign still remains.

So, this go-round, the superdelegates, elected and party officials, big donors and other luminaries, won’t be allowed to vote on the first ballot at the DNC’s nominating convention. If the convention deadlocks, they will regain their voting rights, and who wins in what could be a brokered convention is anybody’s guess at this point. If that happens, post-convention unity may be at serious risk.

This rule is complicated by the DNC’s decision to leave its 15 percent rule in place, which means that to earn a delegate, a presidential candidate must receive at least 15 percent of the vote in the state or congressional district. Winning a presidential nomination has always been a game of numbers. When you have a handful of candidates, getting over that 15 percent hurdle isn’t much of a problem for viable candidates in a relatively open field.

But Democrats are likely to have around 20 candidates vying for votes. According to the RealClearPolitics national average, only two potential candidates find themselves in the enviable position of qualifying for delegates today — former Vice President Joe Biden, who gets 29 percent, and Bernie Sanders, who is just shy of 20 percent.

Senator Kamala Harris is next at 11.8 percent, while the rest of the pack all come in under 10 percent. Obviously, these numbers will vary as state surveys emerge. The percentages we see in polls today won’t hold, in all likelihood, but the very size of the field is going to require some strategic wizardry and some math nerds to plot a path to victory.

Republicans, who allow states to set their limits with a top of 20 percent, saw this scenario play out as one candidate, Trump, was able to win states with a solid base but not a majority, especially early on.

The sheer number of Democratic candidates also poses a challenge for the presidential primary debate process, which the DNC has also changed for 2020. DNC Chairman Tom Perez has made it clear that the party doesn’t want a repeat of the 2016 Republican nominating process, which was chaotic, to put it politely.

In announcing the debate rules for a candidate’s inclusion, Perez outlined how the six Democratic debates in 2019 and the six scheduled in 2020 would be very different from the multi-candidate Republican debates in 2016. Perez said the rules changes would result in debates that were more transparent and more substantive and would give the party’s grassroots more say in who makes it to the stage.

With the first debates in June on NBC and July on CNN, candidates must have earned at least 1 percent or more on three polls (national or one of four early states) between Jan. 1 of this year and two weeks before a debate. But to get the grassroots involved, candidates can also participate in a debate if they have had donations from 65,000 unique donors or 200 unique donors in 20 states.

If the number of candidates who qualify is still too large to be manageable, the debates will be held on back-to-back nights, with each night’s debaters picked randomly, with a maximum of 20 debaters across both nights.

Will these changes be enough to avoid the Republicans’ debate performance in 2016, which produced plenty of sound bites good and bad but very little substantive discussions of issues? It remains to be seen.

Debates are crucial, and good debate performances can change electoral outcomes. In 2012, Newt Gingrich’s strong debate performance helped him win the South Carolina Republican primary. But when eight or 10 debaters are vying for limited time, good intentions aside, sound bites are likely to overwhelm substantive policy.

The Democratic Party has some serious differences that need resolving, and a hotly contested presidential primary process isn’t generally the ideal environment for accommodation. It should be a serious discussion of issues that showcases ideas and leadership. Whether this process delivers a viable candidate for the Democrats remains to be seen.