(NewsNation) — The Democratic presidential ticket is gaining ground in key battleground states as Vice President Kamala Harris and Minnesota Gov. Tim Walz draw big crowds in recent rallies.

Former Minnesota Gov. Tim Pawlenty, a Republican who has previously worked with Walz, joined NewsNation’s “Morning in America” to discuss the recent gains.

“The Harris Walz ticket is going to be much more formidable than many Republicans first thought,” Pawlenty said, adding that Republicans will need to “appeal to those so-called Nikki Haley voters.”

“I don’t know that Trump can change and appeal to those voters now, so he may have to pursue a strategy to make the Harris Walz ticket even worse in the eyes of the swing voters, so they have no choice but to reconsider Trump,” Pawlenty said.

Meanwhile, Harris promised Saturday to work to eliminate taxes on tips paid to restaurant and other service industry employees, echoing a pledge that Trump has made, and marking a rare instance of political overlap from both sides.

“I’m sure it’s frustrating for the Trump campaign. It’s a clever move by the Harris campaign, and it’s an appealing issue. If you’re a service worker in the country and you have to pay taxes on tips, that’s a great thing,” Pawlenty told NewsNation.