Some Sanders supporters struggle to move past 2016 fight

IOWA CITY, Iowa (AP) — A number of Bernie Sanders supporters say they won't let go of the slights from the 2016 Democratic presidential primary fight against Hillary Clinton.

The frustration is notable now that Sanders is a 2020 front-runner, raking in $18.2 million in the first quarter, downplaying concerns about Democratic National Committee bias and highlighting his success in bringing the party around on liberal policies it once resisted.

Some establishment-aligned Democrats worry the party could lose if lingering concerns aren't assuaged.

The acrimony stems from a fiercely fought campaign and a sense among Sanders loyalists that party leaders favored Clinton. DNC leaders scheduled few debates and sometimes slated them for nights with low television viewership. Often opaque delegate allocation rules also contributed to a belief among some that the primary was essentially rigged.