Matt Sinovic, executive director of Progress Iowa, one of the largest left-leaning advocacy groups in the state, said Buttigieg generated considerable buzz with a recent statewide bus tour. He starts another on Saturday. But the Indiana mayor is also swamping his opponents in digital advertising, something that’s been hard to miss in Iowa.

“I cannot overstate how many Buttigieg ads I see,” said Sinovic, pointing to data showing Buttigieg’s national digital spending numbers surpassing Biden almost five-to-one. “It’s just a massive outspending right now.”…

“You might expect that a frontrunner is going to lose some ground as other candidates become more visible,” said Selzer. “It’s not just that there’s not enough numbers to go around. It’s that he’s not wearing well. It’s the trend, it’s the decline.”

Biden’s campaign announced on Friday a new round of digital ad spending in Iowa. And he’s opening a new office in the state, giving him 23 overall as well as 100 staffers.