From Dionne's column in the Washington Post:
Trump’s troubles threaten to go beyond Wisconsin. He could now lose in other big states that vote next, including Pennsylvania, California, New Jersey and possibly even his home state of New York. If this happens, it will be far easier for the Republican Party bosses (such as they are these days) to deny him the nomination. Trump will come to look less like the rank-and-file Republican favorite and more like a flash in the pan.
Second, Democrats Hillary Clinton or Sen. Bernie Sanders (I-Vt.) would lose their ideal opponent. From their point of view, Trump’s collapse may come too early. It’s true that if the very right-wing Cruz were the Republican nominee instead of Trump, the Democratic winner — it’s still likely to be Clinton, despite Sanders’s current surge — would be favored.
But an utter Trump implosion might free the Cleveland convention to turn to someone entirely outside the current crop of candidates, someone unsullied by the ugly and vulgar GOP primary campaign. A sinking Trump would have far less power to resist such an outcome. Democrats need to prepare now for the strong possibility that they will not be lucky enough to run against The Donald. [My emphasis.]Or even, for that matter, Ted Cruz.
I'm going back to a prediction I made several months ago: Paul Ryan will be the Republican nominee.