Should a politician have their own principles and stick to them even if they are unpopular, or is the job of a politician to represent the opinions of their constituents? Electoral Vote puts it this way:
Some voters like their politicians to be completely principled and refuse to compromise those principles, ever. Better a principled loss than half a win. Sen. Ted Cruz (R-TX) is like this and his supporters love him for it. Other people think that politicians shouldn’t actually have any principles. They should represent their constituents and do what their constituents want. When Sen. Kirsten Gillibrand (D-NY) was promoted from being a representative in a rural district in upstate New York to senator of the whole state she instantly switched from being a right-wing Blue Dog Democrat to one of the most liberal senators. She then explained that her job was reflecting the views of her constituents and now she had very different constituents. The same could be said of Clinton. She clearly has some principles (she’s never wavered on gun control or abortion) but now that Sanders has demonstrated that a lot of Democrats oppose TPP and Keystone and support a $15 minimum wage, she is coming around to absorbing their views.
I believe that we have a “representative democracy” and so the representatives should really reflect the views of the voters. If we accept the fact that voters change their views (as they did quite quickly on gay marriage), then why do we believe that our representatives should not change their views based on the views of their constituents?
However, one point that Electoral Vote left out is figuring out just who are the real constituents of a representative. Are they the voters, or are they instead the donors? Especially after Citizens United, it may be that money is more important than voters, not just because politicians can pass laws to disenfranchise voters they don’t like, but because they can sometimes (but not always) persuade voters to change their views, even to the point of voting against their own interests.
Indeed, in this election especially, both Trump and Sanders are popular because of the view that their loyalty cannot be bought.