Nikki Haley

Nikki Haley is an insanely popular Republican that could do serious work in the 2024 primary if push came to shove. 

The former United Nations Ambassador has a reasonably good track record regarding policy but has publically stated that if former President Trump were to run for office in 2024, she would not run against him. 

Haley has been highly critical of former President Trump in the past but seems to be on relatively good terms with him now despite the hiccups.