What do the latest campaign finance reports tell us about Trump’s campaign?

They tell us that he is in trouble. The presumptive nominee had just $1.3m on hand at the end of May. This is not a lot of money by the standards of American political campaigns: 121 members of Congress had more money available than Trump, as did the presidential campaigns of two defeated rivals, Ted Cruz and Ben Carson. In contrast, four years ago, Mitt Romney had $17m at the end of the same fundraising period.

How does that compare with Hillary Clinton?

Clinton’s campaign finance report showed she had more than $42m available. Clinton has already reserved nearly $21m for TV ads in swing states in the coming weeks. Trump has yet to buy a single TV ad since reaching a majority of Republican delegates in early May. Clinton has nearly 700 staffers on her campaign. Trump currently has about 70.

Does this hurt his campaign?

It puts Trump at a major disadvantage. TV advertising is an integral part of American political campaigning and has driven the financial arms race that makes presidential campaigns billion-dollar enterprises. Further, it means Trump doesn’t have the financial resources to hire field staffers to identify potential supporters and turn them out to vote on election day.

Why doesn’t Trump have any money?

Until recent weeks, Trump never tried to raise much money. Although he actively solicited donations online, many of his donors were people who bought hats from his website; he has not solicited supporters for funds. Individual donors can give candidates for federal offices up to $5,400 ($2,700 for the primary and $2,700 for the general election).

How, then, did he win the Republican primary?

Trump became the presumptive Republican nominee by running one of the most unconventional campaigns in modern times, against the most splintered field in history. Despite leading in polls from almost the day he announced, none of his rivals took Trump seriously until he had consolidated his lead. Trump also benefited from unprecedented media attention, which meant that his rallies were invariably covered live on cable news in the US. Although other candidates had far more robust organisations, Trump was able to capture the conservative zeitgeist and the anti-establishment mood of the electorate in a way that other candidates were not.

Will that work in a general election?

Probably not. Unlike a presidential primary, in which Trump can go from state to state appealing only to his populist conservative base, he now has to run a national campaign against a single opponent in an election in which more than 125 million Americans are likely to cast ballots. Trump has to build an organisation capable not just of turning out the true believers wearing his trademark Make America Great Again hats, but also swing voters. For all his appeal, Trump still had great difficulty winning a majority of the vote in competitive Republican primaries, and faces a far bigger challenge winning a majority in a general electorate, of which roughly 30% of voters will be members of minority groups.

But Trump is rich. Can he use his own money?

Yes. Under US campaign finance laws, candidates can give an unlimited amount of money to their own campaigns. The question is how much money Trump actually has. Although he claims a net worth of $10bn, his actual fortune is likely to be far less. Trump has refused to release his tax returns, which would clear up many of these questions.

Furthermore, because many of his assets are real estate holdings, his wealth is not very liquid. So far, Trump has loaned his campaign more than $40m. The question is how much more money he has available, and whether the famously tight-fisted billionaire is willing to invest even more of his fortune in his campaign effort.

Can he still win?

Trump faces an uphill battle. The presumptive nominee is lagging in polls and currently making even normally deep-red Republican strongholds such as Utah and Texas competitive – and the current electoral map favours Democrats. However, even with weak fundraising, it’s possible that major donors could start a superPAC or fund an existing one to support Trump. SuperPACs – nominally independent political action committees – can take unlimited contributions. However, they operate under a number of significant legal disadvantages and cannot co-ordinate with a candidate.

Hillary Clinton also has a number of weaknesses as a candidate, and has been continually plagued by issues of trustworthiness, which have been amplified by the ongoing scandal over her use of a private email server.