Will Wilkinson’s criticism of libertarian populism seems strongest when he writes this:

Second, political parties are coalitions of interests, and the Republican Party is the party of the rich, as well as the ideological champion of big business. A principled anti-corporatist, pro-working-class agenda stands as much chance in the GOP as a principled anti-public-sector-union stance in the Democratic Party. It simply makes no sense.

Wilkinson is right about this up to a point. There are major political obstacles to any “principled anti-corporatist, pro-working-class agenda” prevailing in the GOP, but then it is the party’s support for corporate interests that makes such an agenda so appealing as a break with much of what is wrong with the GOP. Parties are coalitions of interests, and Republicans rely on the votes of a lot of people whose interests are currently neglected by the party’s policy agenda. One reason that the GOP can be “the party of the rich” while relying on the votes of working- and middle-class voters is that it portrays its reliable support for corporate interests as a defense of free markets, entrepreneurship, and small businesses. One virtue of a libertarian populist agenda is that it exposes this fraud and presents an alternative that is still potentially palatable to a conservative electorate. Whether a libertarian populist GOP would be able to win more elections than the party in its current state is unclear, but it is virtually the only alternative on offer arguing that there is something fundamentally wrong with the party’s current economic agenda. Libertarian populism faces entrenched opposition and has a long way to go before it will become a major influence in the GOP, but then the purpose of this agenda is to make significant changes in who and what the GOP represents in practice.