The Economist: “First, as a billionaire, he will not run out of money to finance his campaign. Second, he faces so many Republican opponents that he could grab the nomination with only a modest plurality of the vote. The smart money still says that Republicans will eventually unite behind a mainstream candidate, as they always have in the past. But the world cannot take this for granted. Demagogues in other countries sometimes win elections, and there is no compelling reason why America should always be immune.”

A close associate tells Politico that Donald Trump plans to sign a loyalty pledge “that would bind him to endorse the Republican nominee, and would preclude a third-party run. Trump made the stunning decision, which he has long resisted, to avoid complications in getting listed on primary ballots, and to take away an attack line in the next debate.”

“So his decision to give it up is a sign that he increasingly wants to show his campaign is real and not a stunt. The colorful magnate is also trying to make that point by adding staff in key states, issuing position papers, and pursuing access to primary ballots throughout the country.”

Chris Cillizza: “But  there is absolutely no reason to think that simply by the act of signing this pledge, Trump will somehow be legally bound to not run as anything but a Republican in 2016. He won’t be.”

Jonathan Chait: “All Trump needs is some insult to his oceanic ego to declare any previous agreement null and void. And if Trump does run as an independent, that is the ball game. He wouldn’t even need to appear on the ballot everywhere. A few key states could swing the outcome. For that matter, he could swing the outcome without even making the ballot. All Trump would need to do is campaign as a write-in candidate, and if he persuades a couple percent of the voters to go along, that could make all the difference in a polarized electorate.”

Chris Cillizza: “The summer of Trump looks poised to turn seamlessly to the autumn of Trump. His numbers in Iowa and New Hampshire — as well as nationally — look to have topped off a bit of late, but a) that still puts him in a very strong position, and b) his numbers haven’t dropped off in any meaningful way.”

“Trump’s immigration stance makes him appealing to a large number of conservatives, and his willingness to say whatever he is thinking at any moment conveys a sense of freedom that attracts less partisan Republicans. Trump’s, um, trump card in the race might actually be his unwillingness to accept big-dollar contributions; that’s his biggest applause line at many of his events.”

Amy Walter: Winner and losers from the summer of Trump

“Seeking to avert a 2016 disaster, the Republican National Committee on Wednesday challenged every GOP presidential candidate to sign a pledge not to undertake a third-party bid under any circumstances,” the AP reports.

“The challenge, confirmed by multiple campaigns, is aimed squarely at Donald Trump. And the timing of the pledge suggests an agreement has been reached.  While neither side would publicly confirm late Wednesday that an agreement had been reached, Trump has hinted in recent days the GOP lobbying was beginning to work.”

CNN: “According to sources familiar with the discussions, all signs indicate that Trump will sign a pledge to support the Republican nominee if he loses, and not run as an independent.”