1988 is debatable; it's true that a lot of the campaign focus was on rather trivial matters, but Bush still would have been solidly favored based on the economic fundamentals. It's pretty hard to distinguish between a Bush voter voting on the economy and a Bush voter who felt Dukakis represented a threat to the pledge of allegiance.
The other four, however are clear examples of elections that the Democrats would have won if they had been about the economy, but lost because of foreign policy (1952, 1968, 2004) or focus on trivial matters (2000).
So I'd say us Dems are due for an election that we win that we would've lost if it had been about the economy; we haven't had one since 1940.
