Former Vice President Mike Pence has filed paperwork to run for president, setting up a showdown with his ex-boss, former President Donald Trump.

Mr. Pence plans to formally launch his campaign Wednesday in Iowa and is slated to headline a CNN Town Hall later that day.

Mr. Pence, 63, who also served as governor of Indiana and as a member of Congress, faces a steep climb in the GOP nominating contest. He barely registers in polls and has fallen out of favor with a large swath of GOP voters because he refused to kowtow to Mr. Trump’s stolen election claims.

Still, Mr. Pence sees a path to victory that centers on a message steeped in traditional conservative tenets of limited government.

Jaime Harrison, chair of the Democratic National Committee, welcomed Mr. Pence into the race in the same fashion he has responded to other GOP White House hopefuls: tying him to Mr. Trump.

“Pence pushed an extreme agenda in Congress and the Indiana statehouse before becoming Donald Trump’s MAGA wingman for four years and then campaigning for election deniers last year,” Mr. Harrison said. “Pence’s entrance will no doubt drag an increasingly MAGA 2024 GOP field even further to the extremes.”