the parking lot theory of third parties
Right now, we aren’t seeing a collapse of Donald Trump. Instead, we’re seeing (a) Clinton 2 steady at about 45% in the four way race and (b) Trump moving from about 40% to 43%. That means that the third party vote is collapsing. Johnson is dropping from a summer high of 10% to 4%. How can that be?
My current favorite explanation is the “parking lot” theory of American third parties. Most people today are highly polarized, which means they strongly sort themselves into parties and stick with it. A number of people, including myself, have argued that parties are a sort of social identity. Perhaps not as fundamental as gender or racial identity, but important none the less. The consequence of party-identity theory is that people usually become defensive about their identity and they are loathe to leave it.
“Parking lot” theory is a corollary of party-identity theory. When people are faced with a horrible candidate from their party, they become defensive and don’t want to give it up. They refuse to consider third parties. At best, third parties become “parking lots” for voters who are indecisive or embarrassed until they finally pull the lever for mainstream parties. I suspect that is what resulted in those 10% polls for Johnson. The Libertarian Party was simply the “parking lot” for 5% of American voters who fully intend to vote GOP but are too embarrassed by Trump. There is a real libertarian vote out there, but it is in the low single digits. Definitely not 10%.
I’m not the first to make this argument. In fact, one my BGS* pointed out that this argument appears in Shafer and Spady’s recent book The American Political Landscape. They don’t develop it fully but the historical data is there. In 2016, we see a spike of 10% for the Libertarians but they’ll be lucky to get 5% on polling day. In 1992, Perot peaked in the 30% range but ended up with 19% (still impressive) and then 10% in 1996. In 1980, John Anderson peaked at 20% but ended up with a paltry 7%. Nader 2000 is probably the only modern third party candidate that wasn’t a voter parking lot. He polled consistently in the 2%-4% range and got 3%.
Bottom line: The Libertarians may spoil a state or two this round, but they are doomed to be a voter parking lot.
* Brilliant Grad Students