Vice President Kamala Harris has one overriding weakness as a candidate for president — she is perceived as being to the left of Joe Biden. Ms. Harris has criticized U.S. Immigration and Customs Enforcement, supported single-payer health care and even praised the “defund the police” movement. More recently, opponents have blamed her for what they see as a too-porous southern border.

Ms. Harris will not win Electoral College swing states and the presidency unless she convinces voters that her administration will share the sort of centrist policies and leadership that were essential to the victories of Mr. Biden, Barack Obama and Bill Clinton. And an emphatic and persuasive remedy to that problem would be to pick Gov. Josh Shapiro of Pennsylvania as her running mate.

Mr. Shapiro, who is unpopular with many progressives over energy policy, school choice and other issues, would send a signal that Ms. Harris is not captive to the left and that she puts experience ahead of ideology. Choosing him would add an experienced governor from a swing state who could appeal to many moderate Democrats, independents and some Nikki Haley voters on a multitude of key issues. He would provide balance to the ticket and underscore that there is a place for moderates in today’s Democratic Party.

For those who look at politics as a mosaic of identities, Mr. Shapiro would also reassure Jewish voters — long a key part of winning Democratic voter coalitions — at a time when many of them see hostility and antisemitism coming from some in the far left of the party. Now, some pundits and analysts of presidents and their running mates will wonder if adding an observant Jew to a ticket headed by a Black woman is a ticket to nowhere. But the elections of Mr. Obama and now the surge of Ms. Harris suggest that America is a lot more focused on party unity and stopping Donald Trump than on race and religion. Remember that Joe Lieberman was the first Jewish vice-presidential nominee, in 2000, and he deepened the heft, experience and integrity of the ticket led by Al Gore.

Pennsylvania, of course, is a critical battleground state and a must-win for the Harris ticket. With its 19 electoral votes toward a needed 270, the state has swung back and forth recently, going for Mr. Trump in 2016 by 44,000 votes and for Mr. Biden in 2020 by about 82,000 votes — razor-thin margins of victory that show that the state can be flipped easily with the right messengers and message.

While the history of governors helping to deliver their states is mixed, Mr. Shapiro has an appeal outside of geography — one recent poll found that 18 percent more Pennsylvania voters approve than disapprove of his job as governor — because he is capable of actually bringing together a broad coalition of voters. He soundly defeated his Republican opponent for governor in 2022 by nearly 15 percentage points.