Donald Trump, anxious for a win in Pennsylvania, holds rally in Erie

Republican presidential candidate Donald Trump was speaking at a rally in Pennsylvania on Sunday, his fourth campaign stop in a month in what has become the 2024 campaign's most hotly contested state.

The former president had begun addressing supporters in Erie, in Pennsylvania's northwest corner, shortly after 2 pm local time (1800 GMT). His rally comes one month to the day after his running mate, US Senator JD Vance, held his own event in the lakeside city, and six days before Trump is due to hold another rally in western Pennsylvania, on October 5.

Many allies and informal advisers to Trump privately characterise Pennsylvania as the most important of the battleground states in the Nov. 5 election.

Of the seven competitive states that both Trump and Vice President Kamala Harris, his Democratic rival, have a realistic shot at winning, Pennsylvania is the most populous and awards the most votes in the Electoral College, which in turn is used to select the overall winner of the election.

Trump allies broadly believe that if the former president beats Harris there, he is likely to return to the White House. But if Trump loses to Harris in Pennsylvania, the vice president has the inside track.

In a reflection of the stakes, Harris and Trump have spent hundreds of millions of dollars on ads in Pennsylvania in the months before the election, more than any other state in both gross and per capita terms.

Erie, the site of Trump's rally, is a battleground inside a battleground. Erie County is one of two Pennsylvania counties that favored Trump in the 2016 election against Democratic candidate Hillary Clinton before favoring President Joe Biden against Trump in 2020.

Trump narrowly won the state and the election overall in 2016, before losing both in 2020.

This time around, Pennsylvania is again competitive, according to surveys. Harris leads Trump by 1.6 percentage points in the state, according to an average of polls maintained by polling and analysis website FiveThirtyEight. That difference is well within almost all polls' margin of error.

Trump's next rally in Pennsylvania, on October 5, will take place in Butler, about 100 miles (160 km) south of Erie. That town was the site of a failed assassination attempt on Trump in July. A bullet grazed the former president's ear.