It was supposed to be Jeb Bush, if you asked Democratic honchos in mid-2015, except when it was always supposed to be Scott Walker. Eventually, they insisted, it was always supposed to be Rubio.

But it was never supposed to be Trump.

Clinton circles' initial planning for Bush began even before Democrats' wipeout in the 2014 midterms. In an October 31, 2014 memo, informal confidant and longtime friend Sidney Blumenthal mapped out a "CONFIDENTIAL" path for Clinton, which she then forwarded to aides Nick Merrill, Brynne Craig, Huma Abedin, Philippe Reines and Cheryl Mills, with the note: "Worth discussing elements." Mills then forwarded the note to campaign manager-in-waiting Mook and Podesta.

"The Republican presidential campaign will begin on November 5th," Blumenthal wrote. "If Jeb Bush doesn't run, there is no viable establishment candidate. If he does run, he will be subjected to an unprecedented assault that might culminate in a splintered party, even a third party."

Around that time, an increasingly politically engaged Clinton started telling friends and political advisers that she expected something close to a classic battle about the economy against the Republican establishment's choice.

Six months later, Clinton associates' wariness of Bush and his likely financial firepower was still acute: Democratic pollster Celinda Lake wrote to Clinton adviser Minyon Moore to warn her that she'd been testing Bush's economic message for a client. "It has been remarkably strong. Getting even half of african americans and democrats and two thirds of latinos. Some thought it ended too harsh. But the perspective on the economy has really worked. Now we didn't tell people this was from bush. But it's a warning."

So to take Bush down, Clinton's team drew up a plan to pump Trump up.