Grassley will be a "special guest" at two fundraisers for David Young (R), who was his chief of staff until late May, according to invitations obtained by the Des Moines Register.
The move likely pits Grassley against Iowa Gov. Terry Branstad (R) in the Iowa Senate primary, as Branstad has quietly pushed Iowa state Sen. Joni Ernst (R) to run for the seat.
Both men have been careful to stay publicly neutral in the race to replace retiring Sen. Tom HarkinTom HarkinDistance education: Tumultuous today and yesterday Grassley challenger no stranger to defying odds Clinton ally stands between Sanders and chairmanship dream MORE (D-Iowa), but as the race heats up, it will be interesting to see how involved each gets for their preferred candidate. Former U.S. Attorney Matt Whitaker (R) is also in the race.