Most focus on the what, the what that happened to Biden's campaign in Iowa. They should be seeking to understand the why. Pelosi's ill advised and now failed impeachment gambit over a Ukraine phone call allowed Trump to refocus media attention on Biden's corrupt dealings there. Voters understand the significance of Hunter being paid just short of $1 million for serving on a Ukrainian oligarch's board of directors at a time when the oligarch is being investigated for corruption. The point was driven home by House prosecutor's as they relentlessly drew attention to Trump's desire to investigate Ukraine's corruption during the Obama administration and their meddling in the 2016 election.
From WaPo:
"just five days before the crucial primary here, the candidate was nowhere to be found. Biden spent Thursday gathered with his top advisers at his home in Wilmington, Del., seeking a reset and perhaps a last-ditch effort to save his candidacy"
"happened to Joe Biden was getting gut-punched in Iowa,” he added. “It woke him up, it woke his campaign up and his supporters up. They were complacent"
"Biden’s supporters were growing agitated with the campaign, struggling to point to any one piece of it that has been successful. His organizing operation struggled in Iowa, his fundraising numbers have never been impressive, and his message is often muddled.
One person close to the campaign, who spoke on the condition of anonymity to discuss internal strategy, expects a dramatic reshuffling of his operation if Biden does not show improvement in New Hampshire"
https://www.washingtonpost.com/politics/his-campaign-on-the-line-joe-biden-goes-missing-in-new-hampshire/2020/02/06/4a87c262-4901-11ea-9164-d3154ad8a5cd_story.html?itid=hp_hp-top-table-low_biden-920pm%3Ahomepage%2Fstory-ans