I'm beginning to think it can happen.
True, the Donald has very high negatives. So does Hillary, though, and it will be just as hard to prevent Hillary from winning the Democratic nomination as it will be to prevent Donald from winning the Republican.
Matched in a general election, Hillary will be the Establishment candidate, Tr*mp the "outsider." Since Americans are justifiably sick and tired of the way their government operates, the "outsider," however potentially dangerous and patently bizarre, has the advantage. The outcome might surprise a lot of people.
Hillary's disavowal of free trade pacts certainly is suspect, reversing decades of enthusiastic support. How many of those working class Sanders supporters will switch their allegiance to Tr*mp if their alternative is another Clinton? Labor will reflexively "endorse" the Democratic candidate, but how well will a former Wal-Mart board member serve Labor's interests, and how many rank-and-file union members will play "follow the leader?"
What will happen if voters, who tend to stick to a single party line on their ballots, fail to return the Senate to Democrats? Who would Tr*mp nominate to the Supreme Court? (Nobody has even a vague idea of the answer to that last question.)
Nobody seems to have asked any of the candidates how they might fill jobs like Secretary of the Treasury, chief economic adviser, Chair of the SEC, etc. Tr*mp, hopelessly ignorant of the actual workings of government, would have to depend on "advice" from the likes of Chris Christie and Jeff Sessions. Clinton is most likely to return to the charlatans of her husband's "economically successful" administration, meaning more acolytes of Robert Rubin.
Frankly, I think Bernie Sanders is America's best bet, despite the fears of Establishment black, labor, and "liberal" figures. Compared to Hillary, Bernie is far more likely to win.