When US President Joe Biden recently signed off on a $80m (£64.6m) grant to Taiwan for the purchase of American military equipment, China said it “deplores and opposes” what Washington had done.

To the casual observer it didn’t appear a steep sum. It was less than the cost of a single modern fighter jet. Taiwan already has on order more than $14bn worth of US military equipment. Does a miserly $80m more matter?

While fury is Beijing’s default response to any military support for Taiwan, this time something was different.

The $80m is not a loan. It comes from American taxpayers. For the first time in more than 40 years, America is using its own money to send weapons to a place it officially doesn’t recognise. This is happening under a programme called foreign military finance (FMF).