In the runup to Halloween, there may be no stopping the American consumer. Over the past decade, planned spending on costumes, candy, and decorations has doubled, according to the National Retail Federation, even as broader consumer sentiment has fallen. This year, Americans plan to cut back a bit: One-quarter of those surveyed by the NRF said the weak economy would affect their budgets. But don’t bury Halloween yet. The 10-year trend line suggests it’s very much alive.