Hillary Clinton chose a bitterly ironic party location to thank her massive donor network last week: the grand ballroom of The Plaza, once owned by Donald Trump.

The people gathered for the glum get-together, including hedge fund managers and media titans, had built the most formidable fundraising network ever seen in American politics. They pumped more than $4bn into various Clinton campaigns and related political and charitable groups over four decades. Many of them have been cutting huge checks since Bill Clinton’s first presidential campaign in 1992.