This Washington Post story seems to be the first story in mainstream media that discusses at length the current contest for the Libertarian presidential nomination. The story only covers Gary Johnson, Austin Petersen, and John McAfee.
Nevertheless, although the article is thus incomplete, this seems to be the first time since 1996 that major media has covered the race for the presidential nomination of any party other than the Republican and Democratic Parties. The media did cover the Reform Party’s internal nominating contest in 1996. That was between Ross Perot and former Governor Dick Lamm.
The Reform Party also had a big contest for its presidential nomination in 2000, but little attention was paid to the struggle between Pat Buchanan and John Hagelin.