Further to the discussion that Ramesh and Fred have been having about a convention, Jeremy Carl has a robust piece on the home page about this debate, opposing a white knight:
More important, there is no plausible candidate who represents a “compromise” between Cruz and Trump who could be embraced by the establishment and grassroots. This isn’t a question of a party split between supporters of a conservative candidate and those of a moderate candidate but ultimately compromising on a moderately conservative candidate. What the establishment coup plotters demand is that we “compromise” between our two dominant candidates, who were defined primarily by their hostility to the Washington cartel, by selecting as our nominee someone blessed by it.
This strikes me a key point: I admire Paul Ryan, but he would be exactly the kind of candidate — establishment- and donor-friendly, soft on immigration — who has been rejected by Republican voters in this process.