Donald Trump says he is willing to spend his own money on re-election campaign to beat Joe Biden

Donald Trump has said he is willing to put his own money into his re-election campaign as new polling for The Daily Telegraph shows Joe Biden’s lead is shrinking in key battleground states which are likely to decide the result.

Bloomberg on Tuesday reported the US president was considering spending up to $100 million of his personal fortune on his campaign.

Mr Trump spent more than $60 million in 2016 but such spending would be unprecedented for an incumbent president.

“If I have to, I would,” Mr Trump said when asked if he would put his own money into his re-election bid. Asked how much, he said: “Whatever it takes. We have to win”.

However the US president also argued that doing so was not needed right now, saying that the Trump campaign had “double or triple” the amount of money at this stage of the race as it did in the 2016 election cycle.

The comments come amid new evidence that the race is tightening where it matters - in the swing states that will likely determine whether Mr Trump is given a second term on November 3 or his Democratic rival Joe Biden wins the presidency.

Polling done by Redfield & Wilton Strategies for this newspaper has been tracking the mood in the six states that Mr Trump won by the narrowest margins in 2016: Arizona, North Carolina, Florida, Pennsylvania, Michigan and Wisconsin.

Mr Biden led comfortably in all six states in the last poll in July. In the latest polling from late August and early September Mr Trump has narrowed the gap in all six states, showing that the race has tightened as autumn approaches.

Mr Trump is now ahead in North Carolina by one percentage point, according to the polling. He has also roughly halved Mr Biden’s lead in Florida and Pennsylvania. Mr Biden remains ahead in Pennsylvania and far ahead in Michigan and Wisconsin.

The numbers are still good for the Biden camp, showing he leads in five of the six states. If those figures were the actual result on November 3 then in all likelihood Mr Biden would win the presidency, barring freak results in other states.

However the Trump campaign will take heart from the narrowing gap, given over the summer they faced huge poll deficits as daily coronavirus cases surged to record highs in America.

The reasons for the narrowing are complex and debatable. The drops in daily Covid-19 cases could be a factor, given the president’s handling of the pandemic is disapproved of by a majority of voters, according to many polls.

The party conventions could also have played a part. The polling was taken in the week after the Republican convention, potentially capturing views formed by their messaging and dominance on TV coverage during the preceding week.

However pollsters and pundits have widely noted how the traditional post-convention bounces do not seem to have materialised for either party this year, a reflection perhaps of how many voters already have a firm view on each candidate.

The polling shows Mr Biden is three percent points ahead in Florida, five points ahead in Arizona and Pennsylvania, nine points ahead in Wisconsin and 11 points ahead in Michigan.

Mr Trump is a point ahead in North Carolina. Polls, it should be remembered, are a snapshot of voter thinking at a moment in time rather than a prediction of the final result. Between 600 and 1,000 people were polled in each of the six states.