The Progressives of the early 20th had an amazing run — direct elections of senators, regulation of monopolistic trusts, modernization of public schools, cleaning up the food supply — with only one major blooper: Prohibition.
As David Bernstein notes at "The Volokh Conspiracy", this is a bit of a rosy-colored glasses view:
I’m not a big fan of either the Seventeenth Amendment or of antitrust law, but put those aside; what about, among other things, residential segregation laws in the South and border states (fortunately invalidated by the Supreme Court, much to the dismay of Progressive commentators), eugenics legislation, hostility to the Equal Rights Amendment/support for “protective” law for women only, support for American imperialism (at least via one of the Progressives’ great champions, Theodore Roosevelt–and Woodrow Wilson didn’t exactly distinguish himself with American intervention in World War I, which may be the single greatest “blooper” in American history), and support for state legislation monopolizing certain fields on behalf of incumbent businesses (see, e.g., New State Ice v. Liebmann)?
In any case, Egan's argument is an interesting example of a common failure in our ordinary political discourse to recognize that the liberal/conservative labels change drastically over time. There are lots of cases. I remember Janet Radcliffe Richards giving a (very good, as one would expect from her) interview about Mill on the subject of women and mentioning the 'conservative judge' James Fitzjames Stephen. Now, there's no question that some of Stephen's positions would be considered quite conservative now; but he was a utilitarian like Mill, a member of the Liberal Party like Mill, an advocate of reform like Mill; he just thought that Mill's account of liberalism was incoherent and utopian, and that utilitarianism required certain kinds of coercion that Mill's harm principle disallowed (an argument that has never stopped being made by liberal utilitarians). So it's unclear what is meant by calling Stephen conservative in this context; his right to be called liberal and Liberal at the time was quite as good as Mill's -- better, in fact, since Stephen's liberalism would have been more widely recognizable as liberalism in their own day. There is, of course, a very limited sense in which you can say that Stephen was 'more conservative than' Mill on specific points, but this is a very weak and purely relative sense, useful only for very specific kinds of situation; the fact that Noam Chomsky is more conservative than an old-school Stalinist does not make Chomsky a conservative anything.
Through time there are liberalisms, not liberalism; there are conservatisms, not conservatism. These labels are defined relative to a spectrum that is always changing.
I was going to put this in the next links post, but this is as good a place as any:
xkcd had an interesting comic recently on the make-up of the U.S. Congress through the centuries. It's somewhat misleading; the right/left or conservative/liberal distinction is not actually a stable one through time. But the sense it is used here is stipulated as how one is ranked in a DW-NOMINATE system in terms of who one votes with. That is, if all Congress were to turn Communist tomorrow, we'd still get the same sort of left/right spectrum (assuming that members of Congress were still allowed to vote differently), because 'conservative' and 'liberal' are here relative to other people within the same Congress on the particular non-unanimous issues brought before Congress, not to any particular set of ideological claims. It indicates the internal splay of Congress more than its political leanings. It is to some extent arbitrary which direction we consider conservative or liberal -- DW-NOMINATE does not tell us -- so we're actually just looking at distance of legislators from each other, which is often given a loose 'conservative'/'liberal' label based on certain aspects of economic policy (a pretty divisive area of politics that tends to create a lot of divergence among groups of legislators). These labels can make sense if you are simply looking at legislators in a single Congress, but they don't make much sense at all for comparing legislators in 1990 to legislators in 1890. It's an interesting graphic, and definitely fun. But it's almost bound to be misread, precisely because of this common tendency of thinking of 'conservative' and 'liberal' as timeless and monolithic labels rather than as what they are, pragmatic labels for a given time that loosely cover vast numbers of rather different movements, ideas, and people.