Name of logical fallacy

Candidate B lost the gubernatorial election to candidate A by a razor thin 500 votes. As it happens, there were 501 Amish people that voted in the election all of whom it is believed voted for candidate A. Therefore, the reason Candidate B lost the election is because s/he failed to adopt an Amish-friendly platform.

What do you call this type of fallacy?

Not sure, but could be this:
Fallacy of the single cause

Good question. It sounds similar to blaming the player who made the last out for losing the ball game. But I can’t think of a better name than ToughLife’s suggestion.

Correlation is not causation. Just because the numbers match up doesn’t mean there can’t be more factors at play.

Okay, how about this: the Last Straw Fallacy (named after the proverbial “straw that broke the camel’s back”).

I think that “single cause” is a little more general than “last straw”. Only one straw can be the last one, but almost any cause can be blamed as the single one. In the OP’s example, the Amish would only be the last straw if somehow they got to the polls after everyone else.

The Last Straw Fallacy seems to fit the bill. I’m surprised we don’t hear about this fallacy more often when you consider how many election post mortems there are where pundits try to connect their pet fringe interests to the loss.

It depends on how you formally make the logical argument. I would parse it this way.

If you don’t get the Amish vote, you will lose 500 votes. Candidate lost 500 votes, therefore the candidate did not get the Amish vote. It’s called affirming the consequent. If A then B; B therefore A. If it rains, the street gets wet. The street is wet, therefore it is raining. It doesn’t account for the fact that other forces can be at play.

Although the so-called “Last Straw Fallacy” sort of fits, it is more generally an example of the informal fallacy of post hoc, ergo propter hoc reasoning; that is, ascribing a result to a particular element of the cause rather addressing the entirity of the issue. In the hypothetical provided by the o.p., the supposed singular cause was failing to address the needs of the Amish community; however, it fails to consider that doing so might have alienated even more voters who held a contrary position, or the inclination of Amish voters to vote for Candidate B regardless of the platform, or any number of other parameters that could have affected the Amish vote, notwithstanding the presumably larger base of non-Amish people of whom so few were inclined to vote for Candidate A that it came down to the presumably antagonistic Amish voters. Candidate A should have been cognizant of how his or her positions on various issues affected different demographics and appealed to a broad enough range of voters that no one small identity block was crucial to being elected.

It is the job of pundits to distill news and political results down to a few easily digestible points, just as it is the job of a historian to take the complex sum of history and render it into a narrative and conclusions that can fit within the format of a lecture or textbook. The danger of doing so is losing the larger context that led to a supposed single watershed event or casus belli even though no sane person ever goes to war over a single slight, and no one loses an election because they failed to kiss one baby or shake one voter’s hand. In the case of pundits, they all have particular beliefs or positions into which they like to fit a conclusion which is why such conclusions should be regarded with skepticism, and why roundtable debates or even worse ‘groupthink’ shows are a fundamental waste of time in the sense of learning anything useful about an issue.