The political discontent with the two main party candidates leaves open the possibility of third party candidates pulling larger than historically normal amounts of votes. The last time a third party candidate (as opposed to an independent candidate in Perot) won a significant amount of the vote was the Bull Moose candidacy of Roosevelt. That divide had medium term impact on the power of the Republican Party and serves as a good template to look at what may happen if Johnson has a respectable showing in November.
According to red state, 10% of Sanders voters and 13% of non Trump republican voters are gravitating to Johnson. Using the Real Clear Politics count that’s 3.2 million votes moving into the Johnson column. (1.2 million Bernie + 1.98 million Republicans.) Johnson ran four years ago and won 1.27 million votes leaving a potential current vote tally at 4.27 million votes, which would be 3.3% of the popular vote if 2016 figures are used.
Real Clear Politics has Johnson at 8.6% of the vote meaning 5% is coming from some other source. RCP also has 12.6% of the vote unaccounted for leaving an additional potential 16.2 million votes up for grabs. Johnson is pulling 21% of what Trump and Clinton are pulling leaving 3.4 million of those votes available on a proportional basis. That gives a potential voting pool of 7.7 million votes available to be cast for him. Pulling 7.7 million votes places him at essentially 6% of the popular vote in November.
The not Trump GOP defectors aren’t likely in the Bush-Rubio-Kasich faction. Libertarians are too conservative for the Kasich faction. The Bush-Rubio faction is establishment backed, and a vibrant Libertarian party is a threat since it is an alternate route for the right wing of the GOP. It’s a threat, so the establishment GOP is either holding their nose and voting Trump, or at least sitting on the sidelines so as to not strengthen the threat on the right flank. That leaves the Cruz-Paul-tea party faction as the source that is voting Johnson.
So what happens if Johnson acquires 6% of the vote? The Libertarian Party gains public funding, and hell has no wrath as the establishment and Trump backed GOP. When Roosevelt was able to capture states, but not the Presidency, the Bull Moose faction that was in the GOP was made to suffer for 16 years. The tea party already is a very vocal, but discrete minority portion of the party. Giving life to the Libertarian party will likely cause the majority to crack down on the far right wing of the party. If you want to vote Johnson because you are a Cruz supporter, more power to you. But understand it’s a protest vote. Before you pull the lever think about the future and what’s in the best long term interest of your ideology.