In Washington on Sunday night, the popcorn was popped, the pitchers of election-themed cocktails given a final stir. And then a hush fell over the city as the streets emptied and the professional political class gathered huddled around screens to watch the presidential debate and find out whether Donald Trump would somehow rescue his improbable campaign or pound the final nails into its coffin after a brutal weekend of scandalous recordings and cascading Republican disendorsements.

The consensus going in was that Trump would self-destruct. But he had two saviours: moderators prevented him from rambling and harming himself as much as he otherwise probably would have, and the questions about his appalling remarks came early in the debate. Psychological research suggests that people tend to disproportionately judge events by how they ended.

The consensus in Washington was that Trump had "stopped the bleeding." But 12 hours later the haemorrhaging seemed to have restarted. NBC and the Wall Street Journal released the results of a poll taken before the debate, but after the release of the bombshell tape that had sent Trump's campaign into its weekend death spiral. In a four-way race, it showed Clinton at 46 and Trump at 35, a five-point drop from the previous poll. If you just looked at Clinton and Trump together, she was leading by 14.

The question now is whether the defections restart. If Trump's debate achievement was to arrest his slide at 35 per cent, then it makes sense for Republicans to start jumping into the lifeboats.