Detroit Police Chief James Craig, a Republican and a veteran of police departments around the country, is preparing to challenge Democratic Gov. Gretchen Whitmer in Michigan, potentially giving the GOP a formidable candidate in one of the midterm election’s highest profile gubernatorial contests. Craig has spent recent days meeting with GOP leaders, including Ron Weiser, the chair of the Michigan Republican Party, according to a person familiar with the deliberations. Craig has also spoken with Arizona Gov. Doug Ducey, the chair of the Republican Governors Association, according to a second person familiar with that discussion.