Ben Carson is now Donald Trump's biggest rival for first place in Republican presidential polls.
That dizzying picture leaves many questions unanswered. Most immediately: Can Trump go after Carson — a newbie, beloved by the base, and black — in the same way he went after Jeb Bush, a dynasty, well funded by industry, and soft?
Cruz and Rubio, meanwhile, jockey for third place, which has never seemed so important before. Some candidates, including Kasich, are already ceding Iowa, but we have no idea what things will look like come New Hampshire.
Timothy P. Carney, The Washington Examiner's senior political columnist, can be contacted at email@example.com. His column appears Tuesday and Thursday nights on washingtonexaminer.com.