Hillary Clinton just hit that magic number. By winning the Pennsylvania primary with a 10 percentage point margin, Mrs Clinton crossed precisely the threshold that pretty much everyone agreed was the minimum necessary for her to rejuvenate her fading chances of securing the Democratic nomination.

That prospect is still unlikely. But the fact that the Clinton campaign managed to raise $2.5m in new donations within two hours of her projected victory suggests that her candidacy has been re-energised and can now probably last the duration. With just $9m in the bank at the start of the month and $1m a day in operating costs, there had been serious doubts about whether she could afford to keep her campaign on the road. Those can now be put aside.