Sen. Elizabeth Warren has spent her campaign railing against the donor class, making it known she doesn't want their help. She has publicly bashed millionaires, has sworn off high dollar fundraisers and has refused large checks from Democratic bundlers. But behind the scenes in recent months, former President Obama has gone to bat for Warren (Mass.) when speaking to donors reluctant to support her given her knocks on Wall Street and the wealthy. And if Warren becomes the nominee, Obama has said they must throw the entirety of their support behind her. The former president has stopped short of an...