Here is the latest Iowa news from The Associated Press at 3:50 a.m. CDT

DES MOINES, Iowa (AP) — Former Vice President Joe Biden has made a campaign stop in Iowa, where he bemoaned the tone of Trump-era politics and gave a preview of how he might take on the Republican president should he seek the 2020 Democratic presidential nomination. In Cedar Rapids on Tuesday, Biden said, “It’s our leaders who need to set the tone and dial down the temperature and restore some dignity to our national dialogue.” Biden was on a trip across the Midwest campaigning for Democrats ahead of the midterms.

WASHINGTON (AP) — A top Republican campaign official is criticizing conservative Rep. Steve King of Iowa for his remarks in support of a European political party founded by former Nazis. House Republican campaign chairman Steve Stivers called King’s comments and social media posts “completely inappropriate.” The Iowa Republican is still favored to win another term from his rural district in next week’s election. But after King’s latest remarks, some campaign donors say they will no longer support him.

OMAHA, Neb. (AP) — Federal investigators say a broken rail caused the fiery 2017 derailment in northwest Iowa that released 322,000 gallons of ethanol. The National Transportation Safety Board ruled Tuesday that Union Pacific’s maintenance was inadequate before the March 2017 derailment near Graettinger, Iowa, and Federal Railroad Administration inspectors didn’t do enough to identify flaws in the track.

ANKENY, Iowa (AP) — Iowa environmental officials say they’re investigating the spill of about 1,000 gallons of lime slurry into a tributary of a central Iowa creek. The Iowa Department of Natural Resources says the spill happened over the weekend, when a storage tank overflowed at the Air Gas plant in Ankeny. Officials say a construction company on Monday noticed the discharge of the milky white substance into a tributary of Four Mile Creek.