A longer-term average has Mr. Romney three percentage points ahead there, meaning that Arizona leans a net of seven points more Republican than the average of national surveys.

Arizona showing a seven-point Republican lean relative to national numbers would be fairly normal. That’s about where it was from 1992 through 2004, for instance. The gap was wider in 2008, but presumably because its native son, Mr. McCain, was on the Republican ticket…

But if he does win Arizona it will probably be superfluous, since in all likelihood he’ll already have won states like Ohio, Colorado and Virginia that are closer to the tipping point.

The situation is analogous to Mitt Romney winning a state like New Jersey, which is also plausible if Mr. Romney wins the election by several points nationally. But that doesn’t make New Jersey a swing state — it’s just extra spoils for the winner.