DES MOINES, IOWA — Joe Biden’s campaign lawyer sent an excoriating late-night letter to the chair of Iowa’s Democratic Party over Monday’s caucus meltdown, demanding an explanation for the delayed results.

Dana Remus, general counsel for the Biden campaign, lashed into Iowa Democrats for “acute failures” that forced candidates to take the stage just before midnight without any official results.

“We appreciate that you plan to brief the campaigns momentarily on these issues, and we plan to participate,” Remus wrote in the letter to party chair Troy Price and executive director Kevin Geiken, first reported by NBC News.

“However, we believe that the campaigns deserve full explanations and relevant information regarding the methods of quality control you are employing, and an opportunity to respond, before any official results are released,” she continued.

The party first blamed unspecified “quality checks” for the massively delayed results before pinning the problem on “inconsistencies on the data” after using a new phone app that reportedly failed.

Results were expected to start streaming in as Iowans caucused at 7 p.m. local time, with the final results expected around 10 p.m.

But only 25 percent of Iowa’s 1,765 precincts had been collected by that point — meaning none of the campaigns could declare victory.

Des Moines County chair Tom Courtney said an app created to report results was “a mess” and caucus organizers were reduced to having to phone in their results to state party headquarters, which was, at times, too busy to pick up.

“The app that was intended to relay Caucus results to the Party failed; the Party’s back-up telephonic reporting system likewise has failed,” Remus continued.

“In the meantime, we are on to New Hampshire, on the road to the most important election of our lifetimes,” she wrote later.

Candidates for the first time left Iowa for New Hampshire with no clear idea of who won.