Nikki Haley will explain the standings of the race today.

Nikki Haley, the former governor of South Carolina, who according to polls is leaving Donald J. Trump badly with the primaries in her home state just days away, will hold a campaign event today discussing the state of the race.

“I'm not going to give up,” she said Sunday in Rock Hill, S.C., southwest of Charlotte, N.C., to loud applause. “Why should I give up when 70 percent of Americans have said they don't want Trump or Biden in this election? Why should I give up when 59 percent of Americans say Donald Trump is too old and Joe Biden is too old?

After Tuesday's event, which will take place at noon, Ms. Haley will hold a campaign rally later in the day, and she has other campaign events planned on Saturday during the South Carolina primary. She has previously indicated she plans to stay in the race through Super Tuesday, March 5, when several crucial states, including California and Texas, will hold their nominating contests.

But Ms. Haley is in a precarious position in the race. Mr. Trump, who aired a Fox News town hall event on Tuesday evening, is on track for a decisive victory in the South Carolina primary, according to recent polls, and his position appears even stronger in some states. that follow. Recent polls among Republicans in Texas, for example shows Ms. Haley with less than 20 percent support and Mr. Trump with 80 percent. A national survey of Republican voters last week by The Economist and YouGov singled out Ms. Haley less than 10 percent support and Mr. Trump with 80 percent support.

With just four days to go until the South Carolina primary, Ms. Haley has sought to sharpen her contrasts with Mr. Trump, portraying his legal troubles as an insurmountable burden and predicting that the former president, if he will be nominated, will use the Republican National Committee as “his piggy bank for his personal lawsuits” and will lose in November.

Jasmine Ulloa reporting contributed.