Follow the leaders: you can tell a lot about this campaign from where the candidates travel. That's because where they go is where they need votes.
So with roughly 10 states making up the battleground in this election, and with just 18 days to go until polling day, a useful guide to where matters is to look at the candidates flight stubs.
Ohio, Virginia and Florida are the clear winners of the most visited state prize. All are key to the road to victory mapped out by the campaigns and all are close. Obama seems to be hanging on in Ohio but Mitt Romney has moved to a strong position in the other two. This is significant because history tells us that if a Republican wants to win the presidency, he needs to win Ohio.
Next we have states where the candidates have stopped visiting, like North Carolina. President Obama won this state in 2008 by around 14,000 votes and was competitive there until a few weeks ago, when his challenger began to show a lead.
So Obama's stopped showing up there, and Team Romney is moving people out. "With the increasingly widening polls in North Carolina, we will continue to allocate resources, including key senior staff, to other states", a Romney spokesman said.
Then finally there are the states that are moving onto the radar as shifts in the polls make some attainable, or puts others under threat. So the Obama campaign in particular has been spending more and more time in states where a few weeks ago it was leading.
For example yesterday Obama went to the tiny state of New Hampshire, where he has been ahead for months, but is now coming under pressure from Romney, who happens to have a home in the state.
And then there's the conundrum of Pennsylvania: it's a big state with 20 electoral college votes and Obama has been ahead there for months, but Romney's support has shown a steady rise in recent weeks. So you might think Obama would plan a trip to the state. Not exactly.
The President is doing preparations from this evening, though, at Camp David, the presidential country residence north of Washington, near the border with Pennsylvania. It's a place Obama is said to dislike, but TV stations in Pennsylvania will cover his stay there and hence his campaign hopes he'll get the small bounce he needs to hang on. He might need it - one poll tonight puts Romney ahead there.
Romney's choosing to do his preparations for the third debate in Florida, where he leads in the polls, and where on Tuesday the two men will face off for the last time.
As soon as the debate is over the President flies off to Ohio, where Bruce Springsteen and Bill Clinton were on stage together yesterday, and where Joe Biden will be for three days from Monday. Look no further for the state they all want to win.