President Trump’s reelection campaign has outraised every Democrat in the race, with a huge haul of $46 million in the last quarter of 2019. His campaign manager has Tweet-bragged about the “incredible fundraising numbers” as Democrats worry they’ll face a sizable funding disadvantage.

Yet Democrats are now giving Trump reason to worry. Former New York City Mayor Michael Bloomberg said recently he might spend up to $1 billion of his own fortune to defeat Trump in 2020, whether on his own presidential campaign or in support of a fellow Democrat, if Bloomberg’s not the nominee. That’s a game-changing amount of money. On its own, that would more than double all the money, from all sources, spent to get Trump elected in 2016.

Fellow billionaire Tom Steyer has already spent more than $116 million on ads and other activities to support his own presidential campaign, much of it anti-Trump. Steyer isn’t as rich as Bloomberg and probably can’t match his $1 billion, but he’s an ardent anti-Trumper who’s been a top Democratic donor in recent years. Assuming he’s not the nominee this time around, he could add millions more to Democratic coffers once the general election arrives.

The candidates themselves aren’t doing too badly, either. The top six Democrats in the presidential race raised $131 million in the fourth quarter—three times as much as Trump. Bernie Sanders is the reigning champ, with $34.5 million in fourth-quarter funding, followed by Pete Buttigieg ($24.7 million), Joe Biden ($22.7 million) and Elizabeth Warren ($21.2 million).

Trump’s money goes further at the moment, since he has minimal opposition in the Republican primaries and can use his funding to build out his general-election campaign. The Democrats, by contrast, need most of their money to campaign against each other. But the Democrats will have a single nominee at some point, and generous funding now suggests there’s plenty more where that came from.

That doesn’t mean Democrats will win, even if they vastly outspend Trump. Money buys crucial things in elections, such as staff, voter outreach, community activism and of course advertising. But ads reach a saturation point at which voters tune them out. A large staff could be top-heavy, without enough people in the right voting precincts. And a badly managed campaign can squander plentiful funds.

Hillary Clinton sharply outspent Trump in 2016, with $770 million spent on her campaign in total, compared with $451 million for Trump. Clinton lost, obviously. Her campaign underplayed key swing states such as Wisconsin, while Trump’s campaign was much more adept in the newer realm of online advertising. Part of the problem may be super PACs that can raise and spend unlimited funds on behalf of a chosen candidate, but aren’t supposed to coordinate with the campaign and might spend advertising or outreach dollars inefficiently.