Matthew Dowd, a chief strategist for George W. Bush’s 2004 campaign, observed a sign that Donald Trump knows he’s underperforming in the polls.

“Anytime Donald Trump is attacking the polls, then you know he’s in trouble, as that’s the clear signal every time he does that,” Dowd said on MSNBC Thursday. “Because every other time he hawks the polls, says, ‘here’s how great I am, I’m ahead in everything.’”

He added, “And now he’s attacking the polls, including Fox News, which is kind of amazing.”

Fox News released a poll Wednesday showing Vice President Kamala Harris slightly ahead of Trump in several key battleground states — Arizona, Georgia and Nevada — where he had previously led President Joe Biden. The Trump campaign issued a statement calling it “atrocious polling.”

The Republican nominee has repeatedly fumed at Fox News over its coverage of him despite regularly participating in friendly interviews with its hosts. He was reportedly livid when the network called Arizona for Biden in 2020.

Dowd also predicted how things will develop in seven battleground states over the coming weeks, especially as the Sept. 10 presidential debate looms.

“What is more likely to happen is of those seven states, that the Harris-Walz campaign is more likely to put away some of those other states,” he said, “maybe in the Midwest before Donald Trump can recapture some of the Southern or Southwestern states that he has, and that puts him in tremendous difficulty.”