We’re now well under a year away from the Iowa Caucuses, and an unusually–perhaps uniquely–large Democratic field is forming to compete for the opportunity to face Donald J. Trump in 2020. It is highly appropriate that before the festivities intensify, multiple voice are being raised to remember the wolf at the door before engaging in any intramural fisticuffs.

At the American Prospect, veteran labor political operative Steve Rosenthal offers four “rules” for 2020 Democrats in order to avoid a “circular firing squad” that helps Trump win the general election.

* Don’t try to stifle new ideas, new opinions, or new plans.

* Democrats need a robust debate on the issues instead of misleading or attack ads aimed at tearing each other down.

* Every Democratic candidate should sign a pledge that they will give their wholehearted support to whoever eventually wins the party’s.

The stakes of a general election win could not be much higher. Horrible as having Trump as the 45th president has been, a second term would be potentially catastrophic for progressives. The impact on the Supreme Court alone could be seismic. The battle against climate change could be lost for good. The odds of a stupid war or a global economic meltdown would go way up. And a second loss to Trump would be so discouraging to progressive voters that the Democratic Party’s very future might be endangered. Some activists and operatives think it’s critical the ideological direction of the Democratic Party be decisively turned in one direction or another in 2020. Important as a “struggle for the soul of the party” may be, it cannot possibly be as important as denying Trump’s reelection.