WASHINGTON -- With less than a month to go before the Republican National Convention, Donald Trump sent the first fundraising email of his entire campaign on Tuesday. The billionaire eccentric promised to personally match all contributions up to $2 million.

The email comes a day after a campaign finance report showed that his campaign had just $1.3 million cash on hand entering June, putting him in the largest financial hole of any modern presidential candidate.

It is fairly late for a presumptive major party presidential nominee to be sending their first fundraising email. Fundraising pitches aren’t just useful to pull in money from small-dollar donors, but they also provide important data, enabling the candidate to maximize turnout and engagement from their most active supporters.

The promise to match donations is also a long-used trope in political fundraising emails, but it's impossible to know if campaigns actually deliver on such promises. There is no legal mechanism to ensure those promised matched funds will be donated, or that they even exist.

Trump’s promise to match up to $2 million in contributions should be viewed with skepticism, given that he has repeatedly promised to donate money to veterans groups and other assorted charities and then has either failed to pony up the funds or has only done so after being outed by the press.

Donald Trump for President Have you ever wanted to give $10 to a billionaire?

Editor's note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims -- 1.6 billion members of an entire religion -- from entering the U.S.