Donald Trump's unconvincing performance in the second presidential debate – following the debacle of his 2005 video comments aired the day before – has probably extinguished whatever hopes he may have had of succeeding Barack Obama in the White House in 2017. It was not the novelty of the 2005 remarks which shocked Americans – for the list of Mr Trump's sexist and demeaning utterances is long and extensive – but the crudity. True to form, Mr Trump tried to slough off the remarks as nothing more than "locker room talk", and then sought to draw attention to Bill Clinton's alleged sexual misconduct by appearing alongside several of the former president's accusers present in the debate audience.

The last rites have been delivered for the Trump campaign before, only for the indefatigable businessman to bounce back in opinion surveys. The prevailing sentiment this time, however, is that Mr Trump's remarks are beyond excusing, and that Hillary Clinton may have been right along with her suggestions that his character, judgment and temperament are fundamentally unsuited to high office. Few women voters, even those hailing from Mr Trump's key support groups in economically depressed regions of the Midwest, could be expected to write this episode off as blokey banter rather that an indication of a misogynistic streak.

The rush of Republican grandees distancing themselves further from Mr Trump and/or condemning him outright tends to reinforce the view that his campaign is listing badly and beyond salvaging. Indeed, so bereft are mainstream Republicans at where Mr Trump is taking the party that some office-bearers have begun calling for him to be disendorsed and replaced with a more moderate candidate. This option was broached before the Republican convention and rejected as too impractical and divisive – so it's hard to see what good could come of it now, less than a month out from polling day and with Mr Trump warning he will stand as an independent if disendorsed.

The repercussions of Mr Trump's candidacy will continue to play out in Republican ranks for months, possibly years to come. Indeed, so irreconcilable do the differences between the party's moderate and Tea Party wings appear that a permanent split would not surprise. A Trump drubbing could well work to the advantage of moderates as they seek to retain control of the party, especially if Republicans keep their majority in the House of Representatives majority and peg back the Democrats' Senate majority. A respectable Trump showing, however, may well embolden the Tea Party to keep pushing its populist agenda hard.

Moribund though Mr Trump's campaign now looks, it's still possible Mrs Clinton could stumble, allowing him back in the race. The former First Lady is also widely disliked, mostly because she promises business as usual whereas he's the change candidate. However, whereas Mr Trump's always looked (and acted) like an accidental candidate, she's the consummate professional. Now, at last, she has the momentum to win.