And while Warren remained largely off the air until this month, Buttigieg has carpet-bombed the state with digital and TV ads, boosting his name ID. The South Bend mayor also delivered a standout speech to 13,500 Democrats at a marquee political event early this month.

“You have to wonder whether she peaked too soon,” former Iowa Lt. Gov. Patty Judge, co-chair of the advocacy group Focus on Rural Iowa, said of Warren. “In Iowa, she is wearing some — [it’s] like she established her endorsers and her delegates and that’s all there is.”

While the top-polling candidates are sure to rise and fall before the Feb. 3 caucuses, a dozen Democratic activists, county chairs and strategists in the state said Warren is no longer viewed as the prohibitive frontrunner there. Her performance reflects her struggles of late nationally, including one poll out Tuesday that showed her support cut in half in the span of a month.