You can see in both the Paul op-ed and the Johnson interview that major-party politicians are nervous about being tagged with a label that seems to imply a rigorous and radical platform covering a wide range of issues. But if you can call yourself a conservative without necessarily endorsing everything that William F. Buckley Jr. and the Heritage Foundation — or Jerry Falwell and Mike Huckabee — believe, then a politician should be able to be a moderate libertarian or a libertarian-leaning candidate. I wrote a book outlining the full libertarian perspective. But I've also coauthored studies on libertarian voters, in which I assume that you're a libertarian voter if you favor free enterprise and social tolerance, even if you don't embrace the full libertarian philosophy. At any rate, it's good to see major officials, candidates, and newspapers talking about libertarian ideas and their relevance to our current problems.
I was thinking on this question yesterday, and came up with a half-baked theory that libertarians distancing themselves from "libertarian" is a perverse indication that, for the first time since maybe the mid-'90s, libertarians are making some actual headway in the political process. When the best that small-l'ers got for a decade was some private-sector/pop-culture fun and the back of George W. McCain's hand, the term could bask in a vibe of Quixotic/crazy independent outsider with no hope and maybe no aspiration to sit at the Adult's Table. Now that the brand has swollen a bit (partly as a result), with some significant overlap with unsated anti-government sentiment sweeping the land, well, the long knives are out, so better to retreat from the radical-sounding word lest you be subject to more journalistic scrutiny than the president of the United States.
Or maybe it's just a coincidence, etc.