A new NBC News/Wall Street Journal poll illustrates something obvious to anyone watching this campaign: all of its energy comes from love or hate of the president.

When asked if their vote is “more for Barack Obama,” or “more against Mitt Romney,” Obama supporters in the poll overwhelmingly cast their decision as an affirmation of the president, with 72 percent saying it is for Obama. Only 22 percent describe their vote as against Romney.

On the other hand, 58 percent of Romney voters say their decision is largely about President Obama, while just 35 percent describe it as for Romney.

This is not surprising, because most presidential elections with an incumbent president ultimately come down to whether the electorate is ready to fire or rehire that person.

But the poll explains both campaigns’ approaches. Obama aides are trying to turn the election into a choice between two competing visions of the country and are determined to force Romney to declare his positions, even as the former governor tries to avoid spelling them on out on key issues like immigration.

Meanwhile, Romney spends nearly all of his time bashing President Obama’s record on the economy, arguing that is grounds enough for voters to remove the president from office. Many candidates can’t wait to spell out their records and positions, but the former governor wants to turn the election into a referendum on the president’s record.

The poll also explains why Republicans are not worried about turning out their base, even though many in the party are not every excited about Romney. In the minds of Republican strategists, President Obama is the great unifier, rallying evangelicals, Tea Party members, businessmen and moderate Republicans to Romney.

For Democrats, it illustrates both a strength as well. Despite consistent complaining from liberal activists that he is insufficiently progressive, Obama’s support among Democrats is extremely high as the poll suggests.

Follow Perry Bacon Jr. on Twitter at @perrybaconjr