After the Democratic National Committee (DNC) provoked criticism by favoring Hillary Clinton’s campaign in 2016, you’d think it would have learned its lesson about trying to game the nominating process. Apparently not. The DNC has issued eligibility criteria for its presidential candidate debates that threaten to quickly winnow the field—nearly five months before the Iowa caucus and New Hampshire primary.

According to a projection by FiveThirtyEight, only 6-8 of the 23 announced candidates are good bets to qualify for the third debate in September, and only another 6 have decent shots at qualifying. Those in a precarious position include Gov. Steven Bullock of Montana, the only candidate who has won statewide in Trump country.

What’s the rush to narrow the field more than a year before Election Day? Doing so places a greater premium on first impressions, which often are misleading, and it magnifies the advantages of the early front-runners, who receive disproportionate media attention.

All in all, efforts to winnow the field early suffer from three serious problems. They are unnecessary—the primaries next year will narrow the field quickly enough. Moreover, a rush to judgment increases the risk of an incorrect judgment. Finally, the DNC’s strategy may hurt its 2020 nominee in the same way it hurt Hillary Clinton in 2016. By pushing a process that will be seen as unfair to many candidates, those candidates’ supporters may be less enthusiastic about the eventual nominee.