Chris Cillizza: “For party leaders who’ve lined up with Trump amid polling that suggested he was running surprisingly competitively against Democrat Hillary Clinton, the time is rapidly approaching to either hop off the Trump train or decide you are riding it all the way to Nov. 8.”

“At the moment, it appears as though most party leaders are trying to dangle a leg off the train while still holding on.”

For members: The GOP Resumes Its Unraveling

It actually took Hillary Clinton four days to concede the Democratic nomination after Barack Obama secured the necessary delegates in 2008.

As NBC News reported at the time:

“Advisers indicated earlier Tuesday that the former first lady would publicly acknowledge in her speech that Obama had crossed the delegate threshold. But she changed her mind and refused to do so … Her advisers said they considered the delegate numbers to be unreliable, even as the AP estimated Obama had several more than the 2,118 needed to nominate.”

Rick Klein: “If delegates didn’t exist, and the popular vote alone counted, Hillary Clinton would be the Democratic nominee. If superdelegates didn’t exist, and only pledged delegates determined the outcome, Clinton would be the Democratic nominee. If only superdelegates mattered, and party insiders alone chose the presidential candidate, Hillary Clinton would be the Democratic nominee. As it is, under the set of rules all candidates knew were in place when they entered the race, Hillary Clinton will be the Democratic nominee.”

“Bernie Sanders has railed against a ‘rigged’ system and a closed process he says disenfranchises his supporters. But the fact is that, where the world now stands, the only way Sanders can become the Democratic nominee is if party insiders rig the process for him.”

First Read: “But you also have to give credit to Sanders. It’s really not fair to say he lost this contest; instead, he gave Clinton a race that no one saw coming, especially over the last three months.”

NBC News/SurveyMonkey: “While some of the 2016 candidates questioned the fairness of the presidential nominating process, a majority of American voters have a different opinion. Although each party employs different nomination rules, an identical 59 percent majority of Democrats and 59 percent of Republicans think that the process for selecting their presidential nominee is fair.”

New York Times: “In an unusually coordinated series of attacks leveled from congressional offices and the Senate floor, in state capitols and sidewalk protests, Democrats excoriated Mr. Trump as racist and demanded that Republicans either stand behind his comments or condemn him and even rescind their endorsements of his candidacy.”

“Democrats received unexpected ammunition from Mr. Trump himself, who, in an extraordinary conference call with allies on Monday, urged them to defend his criticisms of a federal judge’s Mexican heritage — and then rebuked his campaign staff for having suggested otherwise.”

Politico: Trump train derails on Capitol Hill