As an Obama supporter, I am frequently asked by Hillary Clinton supporters to explain by views on him. The conversations have a tendency of devolving into bitter arguments over what is not known about him, or end with a blanket refusal to consider voting for him... "Not until he explains what this "change" thing is all about," they say. 

These conversations about change and reform inspired me recently to re-read Richard Hofstadter’s 1955 book The Age of Reform. The book won Hofstadter the Pulitzer for its cogent and extremely well done appraisal of American social and political reform movements from 1890 to the Second World War.

The following quote stuck out to me, as it so clearly provides an analysis (in my opinion) of this question about the meaning of change, why as a campaign theme I think it’s intentionally kept vague, and why I don't think it's a huge deal.

On the undercurrents of Theodor Roosevelt’s run for the presidency in 1912 under the Progressive/Bull Moose Party, Hofstadter writes:

“…By “Progressivism” I mean something more than the…party formed by those who supported Roosevelt… I mean rather that broader impulse toward criticism and change that was everywhere so conspicuous after 1900, when the already forceful stream of agrarian discontent was enlarged and redirected by the growing enthusiasm for middle-class people for social and economic reform. As all observant contemporaries realized, Progressivism in this larger sense was not confined to the Progressive Party but affected in a striking way all the major and minor parties and the whole tone of American political life. It was, to be sure, a rather vague and not altogether cohesive or consistent movement, but this was probably the secret of its considerable successes, as well as its failures. While Progressivism would have been impossible without the impetus given by certain social grievances, it was not nearly so much the movement of any social class, or coalition of classes, against a particular class or group as it was rather a widespread and remarkably good-natured effort of the greater part of society to achieve some not very clearly specific self-reformation. Its general theme was the effort to restore a type of economic individualism and political democracy that was widely believed to have existed earlier in America and to have been destroyed by the great corporation and the corrupt political machine; and with that restoration to bring back a kind of morality and civic purity that was also believed to have been lost.”