A group of Arizona voters is suing Republican Gov. Doug Ducey to try to force him to call a special election to replace their late Sen. John McCain.
The federal lawsuit announced Thursday alleges that Ducey's September appointment of Jon Kyl to fill the seat until the 2020 election violates the Constitution.
State law says a special election is to be held at the next general election date. Because McCain died on August 25 it was too late for this year's November ballot.
Ducey spokesman Patrick Ptak called the lawsuit "frivolous" and said the governor executed the laws as required.
McCain's seat would normally be up for election in 2022.
The 17th Amendment requires a popular vote for Senate seats but allows state Legislatures to let governors make temporary appointments.