From “Pennsylvania, the crucial battleground in America’s election” at The Economist:

“On july 21st Matt Roan, chair of the Cumberland County Democratic Committee, hosted a meeting with volunteers. The event took a turn when Mr Roan stopped to read a statement from Joe Biden announcing his departure from the presidential race. “There was this sort of sense of sadness—and then immediate hope,” Mr Roan recalls in his office, which overlooks the Pennsylvania state capitol. The activist speaks highly of Mr Biden but acknowledged that “things were not looking good” at the time. The rise of Kamala Harris attracted a surge of volunteers to a county that favoured Donald Trump by around 18 points in 2016 but only 11 points in 2020. If such improvements hold there and in other areas like it, Ms Harris would probably win the state and the presidency.

Both campaigns see Pennsylvania as a fulcrum of the 2024 election, and for good reason. The Economist’s forecast model suggests that the state—with its 19 electoral-college votes, the most of any swing state—is the tipping-point in 27% of the model’s updated simulations, meaning it decides the election more often than any other state. Mr Trump wins only 7% of the time when he loses the Keystone State. Indeed, he narrowly won Pennsylvania in 2016, and then he lost by 80,000 votes out of nearly 7m cast in his unsuccessful re-election bid four years later.

….The messaging war is a study in contrasts. Ms Harris seeks to define herself in uplifting ads while warning in others about Mr Trump’s effect on the economy, reproductive rights and American democracy. As one of the most famous people in human history, Mr Trump doesn’t spend time introducing himself to voters. His ads and rhetoric relentlessly seek to paint Ms Harris as an out-of-touch leftist responsible for inflation and migrant crime. Such fear campaigns have found success before in presidential elections, but J.J. Abbott, a Pennsylvania Democratic strategist, argues that “there may be some limitations on how much these dark, brutal ads on those issues may work” this time, citing similar unsuccessful efforts mounted by Republicans in recent statewide races.

Mr Trump has also drawn attention to Ms Harris’s past opposition to natural-gas fracking, an important industry in western Pennsylvania, which she now supports. The issue may be top of mind in those energy-producing regions but elsewhere voters often express indifference. “It is not a slam dunk for any politician…to think that Pennsylvania is monolithically in support of further energy exploration,” says Stephen Bloom, vice-president of the Commonwealth Foundation, a centre-right think-tank. “No one has ever said the word fracking to me” while campaigning, says Stella Sexton, vice-chair of the Lancaster County Democratic Committee. She says she hears more about the cost of living and reproductive rights.

For many years a blue state that also elected moderate Republicans, Pennsylvania voted about three points to the right of the country in 2016 and 2020. Since 2008, the percentage of voters registered as Democrats has declined while the share of Republicans has grown. Republican registrations outpaced Democratic ones this year until Ms Harris entered the race (see charts). Democrats argue that some of the Republican gains have been offset by a rise in left-leaning independents.

Harris supporters are particularly proud of their ground game. The campaign has over 350 staffers across 50 offices in Pennsylvania, 16 of which are located in rural areas that Mr Trump won by double digits four years ago. The idea is to chip away at support in heavily Republican areas even when Ms Harris doesn’t have a chance to win outright. “They’re play-acting at trying to do better in the rural counties,” argues Mark Harris, a Republican strategist. “This will once again be an extraordinarily divided election between densely populated suburbs versus exurban and rural communities.”

Republican efforts appear more scattered, with a constellation of groups working on turnout efforts. Postal voting is a priority. In 2020 Mr Trump actively discouraged mail-in voting but has since shifted his rhetoric, albeit inconsistently, in the hope of cutting down the Democrats’ advantage.

If Mr Trump wins Pennsylvania, it will show that he put together a coalition of low-propensity white working-class voters and religious voters, says Ryan Shafik, a Republican strategist, and would probably also have attracted “a good amount of newer minority voters”. Ms Harris will have to reassemble Mr Biden’s coalition built on strength among urban and minority voters, as well as continuing to make inroads into the state’s suburbs. Her current lead in Pennsylvania, according to a polling average maintained by FiveThirtyEight, a data-journalism outfit, is less than two percentage points. For all the money pouring in, the race remains a virtual tie.”