On the rally stage in Philadelphia, he cut the figure of a man destined for the highest office.
No one worked the crowd better and a barnstorming performance went down a storm inside the Temple University arena.
Which begs the question: why wasn’t Josh Shapiro picked?
Kamala Harris’s choice of liberal-leaning Tim Walz has pleased Democrats, no doubt. Chemistry, we’re told, was the clincher for the partnership.
Read more: Could Walz be most progressive VP ever?
Harris is also attracted to his backstory, plain-speaking and political heft on the likes of reproductive rights and gun control.
But if there’s Democratic satisfaction with Walz, there is surprise that 51-year-old Shapiro wasn’t the choice.
He’s a politician with a 60%+ approval rating, sure-footed and moderate enough to settle the horses in Democratic curious-yet-reluctant parts of the country.
As Pennsylvania governor, Shapiro would be a safe bet to lock in the 19 electoral college votes on offer in the state, hugely important in the race for the White House.
On Tuesday evening, however, Shapiro told the Philadelphia crowd, “I love being your governor” and vowed “to continue pouring my heart and soul into continuing to serve you every single day,” before giving the stage over to Harris and Walz.
So why not him? Reportedly, he and Harris didn’t really hit it off in the ‘chemistry test’ interview.
Her head would also have been turned by criticism from pro-Palestinian activists of the Jewish governor’s positions on the Israel-Hamas war, even though they are aligned with others who made the shortlist.
Protests, whatever their foundation, would drag Harris towards awkward territory and difficult questions.
Then there’s ambition. Shapiro is seen as a potential contender for the presidency at some point in his career – Walz, on the other hand, has let it be known that’s not on his radar.
It’s clear which working dynamic would best foster mutual trust between a number one and two.
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A priority for Harris is a working relationship that will thrive in office. She has to get there first.
In making her choice of running mate, she has made the biggest choice of her political career.
It’s also the biggest gamble.