The president's campaign is placing more importance on Pennsylvania amid growing concern that his chances of clinching Wisconsin are slipping, Trump campaign sources tell Axios.

Driving the news: Pennsylvania, which has 20 electoral votes, twice Wisconsin's number, actually has been trending higher in recent public and internal polling, a welcome development for the campaign.

• "We used to think Pennsylvania would be harder to secure and Wisconsin was in the bag. Now it's vice versa," a Trump campaign adviser said.
• But remember: Trump won both in 2016. If Wisconsin slips, he has to make up the numbers elsewhere.

What we're hearing: The campaign sees the "path of least resistance" running through Florida, North Carolina, Pennsylvania, and some combination of Wisconsin, Michigan, Arizona, Minnesota and Nevada, sources close to the campaign tell Axios.

• The apparent gains in Pennsylvania come amid Trump's anti-Biden messaging on fracking and trade, as well as law-and-order rhetoric that aides believe plays well with the state's white, working-class voters.

A smart analysis from FiveThirtyEight's Nathaniel Rakich details how the entire election could hinge on Pennsylvania:

• "Pennsylvania is so important that our model gives Trump an 84 percent chance of winning the presidency if he carries the state — and it gives Biden a 96 percent chance of winning if Pennsylvania goes blue."

In September alone, six of the Trump campaign's top surrogates have been deployed to Pennsylvania, including Ivanka Trump, Eric Trump, Donald Trump Jr. (twice) and Vice President Mike Pence.

• Trump will make his third visit to the state this month on Tuesday, for a rally in Moon Township.
• “Wisconsin and Pennsylvania are both in our plans, which you can tell by the travel schedules of both the president and vice president," Trump campaign communications director Tim Murtaugh told Axios. "Just like in 2016, President Trump will win Wisconsin and Pennsylvania despite what pundits and prognosticators spout.”