The groundwork laid by Trump’s sizable Iowa staff, with 10 paid operatives and growing, is the clearest sign yet that the unconventional candidate is looking beyond his summer media surge and attempting to win February’s first-in-the-nation caucuses.

This is becoming a cause of concern for rival campaigns.

“I see them as a major threat to all the other campaigns because of the aggressiveness of their ground game,” said Sam Clovis, an Iowa conservative who leads former Texas governor Rick Perry’s campaign.

“You cannot swing a dead cat in Iowa and not hit a Trump person,” Clovis continued. “It’s unlike anything I’ve ever seen. . . . Every event we go to — the Boone County Eisenhower Social, the Black Hawk County Lincoln ­Dinner, the boots-and-barbecue down in Denison — the Trump people are everywhere with literature and T-shirts and signing people up.