If you look at the membership and donation data put out by the Libertarian Party [LP] and Google trends, the LP stopped gaining ground when they started running former Republicans instead of principled candidates for President. In short, the LP’s pragmatism has not been pragmatic in building the party. Votes maybe, but party growth itself has stifled.
While these candidates did get more votes, you cannot necessarily judge the growth of the party by that metric. Rather, the votes may be more of a protest vote against the 2 party system as Gary Johnson’s percentage in Maine when the Grand Old Party did not seat Maine Ron Paul delegates in 2012.
Also, Gary Johnson did well in polls prior to much campaigning, and, as The Young Turks have pointed out, people may have just been so fed up with their choices that they said they would consider Gary Johnson sight unseen. However, after a number of botched media appearances, his poll numbers decreased. This would indicate that the Johnson vote was more of a “I don’t like Hillary or Trump” vote than a “I’m a Libertarian” vote.
What you really need to look at is party membership, which has been down ever since the LP ran Bob Barr. While there has been significant growth from the Bob Barr run to the Gary Johnson run, it has not matched the levels when Harry Browne was the candidate. Gary Johnson did champion some controversial issues. Therefore, we cannot attribute those gains to moderation and avoidance of fringe issues.
While I appologize for not being able to find the membership numbers published by the LP anywhere online, you can see plots of the Google trends that paint a similar picture at the in the post
Reposted from Quora
*An arguably shallow look at the data if I do say myself, but it is still data based no matter how many cherries I pick. muhahaha.