PHILADELPHIA — JD Vance, the Republican senator from Ohio chosen as a running mate five weeks ago by former President Donald Trump, came to this overwhelmingly Democratic city Monday with a tough assignment.

Trump's lead in the critical swing state of Pennsylvania has evaporated over the past month as Vice President Kamala Harris' nascent presidential campaign has enjoyed a vibe-driven surge in polling, fundraising and momentum.

Harris and her running mate, Minn. Gov. Tim Walz, are likely to enjoy yet another bounce this week from the political pageantry of the Democratic National Convention in Chicago.

Vance, seeking to kill the Democratic vibe, cast Harris as a danger to America's economy while speaking to a small crowd of supporters in the warehouse of a medical waste management company.

How would he clean up the troubling optics of losing the lead in Pennsylvania?

Vance's answer: Just don't believe polls.

The math is real, even as Vance discounts it. Pennsylvania is now a statistical tie between Harris and Trump, according to an average of polls compiled by RealClearPolitics.

Trump's Pennsylvania lead stood at 4.5 percentage points on July 21, the day President Joe Biden dropped his bid for a second term and endorsed Harris as his replacement at the top of the ticket.

I asked Vance if he believed in the polling and, if so, how he and Trump would make up that........

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