Balderdash! The outcome of the 2000 presidential election, supposedly "decided" in the courts, was really decided by the voters of Florida. Here's why:
Bush won in 2000 because of Florida's electoral votes. Bush won Florida's electoral votes because he had 537 more votes than Gore when the U.S. Supreme Court stopped the recount in Florida. It's safe to say that not a single Florida voter anticipated the events following the closing of the polls in Florida. It's also safe to say that voters who cast valid ballots for Bush, valid ballots for Nader, and invalid ballots for Gore decided the election in Bush's favor.
Suppose Floridians had cast 538 fewer valid votes for Bush. The U.S. Supreme Court might have stepped in with Gore ahead by one vote. Would the U.S. Supreme Court have stopped the recount there? We'll never know.
Suppose Floridians had cast 536 fewer valid votes for Bush, giving him a lead of only one vote when then U.S. Supreme Court stepped in. Would the U.S. Supreme Court have let that result stand? We'll never know.
Suppose 538 of the 97,488 Floridians who voted for Nader had voted for Gore, instead....
In a State where there's a close race (as there will be in several States this year), individual voters have no way of knowing how close the race might be. Nor do they have any way of knowing how many votes might be invalidated for one reason or another. Nor do they have any way of knowing how a recount might proceed, or knowing at what point the courts might step in (if at all), or knowing what the courts might do if and when they step in.
In other words, the outcome of a close election is unpredictable. Tyler Cowen's dictum, therefore, strikes me as pure hindsight. The outcome of an election, even one that is "decided" in the courts, does depend on voters.
The only sensible thing to do when you anticipate a close election in your State, and you favor a particular major-party candidate, is to vote for that candidate. If you don't vote, or if you vote for a third-party candidate, you are effectively voting against your favored major-party candidate.
Will your vote make a difference? It might. You can't know in advance. Therefore, you should vote as if your vote will make a difference.