Former Vice President Mike Pence filed paperwork on Monday declaring his presidential candidacy, embarking on a long-shot marketing campaign in opposition to the previous president he served below, Donald J. Trump.

Mr. Pence, who filed the mandatory papers to run with the Federal Election Commission, has polled within the single digits in each public survey taken to this point, properly behind Mr. Trump, who has reshaped the Republican Party over the past seven years.

The former vice chairman is anticipated to formally announce his marketing campaign at a rally outdoors Des Moines on Wednesday, a day after former Gov. Chris Christie is expected to enter the race and the identical day Gov. Doug Burgum of North Dakota is ready to hitch.

Mr. Pence is planning to marketing campaign extensively in Iowa, the primary nominating state and a spot the place his hard-line conservative positions on points like abortion may attraction to evangelical voters.

Advisers to Mr. Pence, a former governor of Indiana, see Iowa as geographically hospitable to the model of conservatism he practiced earlier than the Trump period. And he’s making the guess that sufficient vestiges of the previous Republican Party stay to offer his message broad attraction.

Mr. Pence, whom the celebrity-obsessed Mr. Trump used to confer with as “out of central casting,” was a stalwart supporter and defender of Mr. Trump over the latter half of the 2016 presidential marketing campaign as his working mate, at a time when Mr. Pence was going through a troublesome re-election effort in Indiana.

He was Mr. Trump’s most loyal advocate all through their time in workplace collectively.

But Mr. Trump started a stress marketing campaign on Mr. Pence to thwart Joseph R. Biden Jr.’s Electoral College victory from being licensed after Mr. Trump misplaced the 2020 election. Mr. Pence refused to make use of his ceremonial function overseeing the certification on the Capitol on Jan. 6, 2021, to advance Mr. Trump’s goals.

That day, a pro-Trump mob attacked the Capitol, with a few of Mr. Trump’s supporters chanting, “Hang Mike Pence!” Since then, the cut up between the 2 has turn into irrevocable.