At issue are absentee ballot request forms that the three counties have mailed to most registered voters pre-filled with information, including names, dates of birth and a voting pin number that few people know.
Voters just have to review, sign and return the forms to get ballots mailed to them beginning Oct. 5. More than 70,000 people have requested ballots in the three counties.
The lawsuits argue that the counties' mailings violate a directive from Iowa Secretary of State Paul Pate, who told local officials last month that the forms must be mailed blank in order to ensure uniformity statewide. Pate's office says it is investigating the three counties.
County officials say they are acting within their authority to promote absentee voting during the coronavirus pandemic. They say that leaving the forms blank would threaten to disenfranchise people who do not know their voting pin or driver's license numbers, either of which must be provided under the state's voter identification law.
Under a new law passed by the Republican-controlled Legislature, auditors cannot use their databases to fill in blank pin numbers on the forms as they have done in past elections. Instead, they must try to contact those voters by email or mail to correct errors themselves, a time-consuming process that will not always be successful.
Democratic-leaning groups have filed a lawsuit challenging the law as an unconstitutional barrier to the right to vote. A hearing is scheduled for late next month.
Republicans say that requiring voters to provide their own information is a safeguard against fraud.
Unlike the two Democratic-leaning counties sued by Trump's campaign last week, Woodbury County voters supported Trump over Hillary Clinton in the 2016 campaign. Democrat Patrick Gill, the long-serving county auditor, was named as a defendant.
Gill's office said last week that it sent out about 57,000 forms and voters had returned 11,000 of them.
Trump met with officials Tuesday in Cedar Rapids to discuss a wind storm that devastated the state last week. About 51,000 voters in surrounding Linn County have returned their absentee ballot request forms, auditor Joel Miller said.
The lawsuits argue that any absentee ballots that are cast in response to the improper mailings would be “subject to challenge and may not be counted in the 2020 general election.” They seek court orders that invalidate returned forms and require those voters to fill out new blank ones.
A hearing on the campaign's request for a temporary injunction in the case against Linn County is scheduled for next week. A judge on Tuesday set a hearing in the Woodbury County case for Aug. 28.