CINCINNATI - Inside a peeling former nightclub here, Obama volunteers are perched on any seats they can find. Trays of half-eaten sandwiches line an old mirrored bar.

But if this campaign office conveys a casual, ragtag feel, it belies a sprawling operation with an intricate chain of command, volunteers who have been here for years, and a lexicon worthy of the military.

After extensive test runs the past few weekends for this Election Day get-out-the-vote machine, an Obama staff member held one final meeting with volunteers in a back room the other night, intoning, "Next Tuesday, it's showtime!"

The Kenwood Romney Victory Center -- one of but three in this county around Cincinnati, five fewer than the Obama camp -- is 10 miles and a world away. Inside a suburban office building populated by insurance firms and walk-in medical clinics, there are no dry runs, no flowchart bureaucracy and fewer young faces; many of the 20 or so volunteers are north of middle age.

What there is, is passion.

As a marathon campaign in Ohio nears a conclusion that its weary citizens surely yearn for, the contest between President Obama and Mitt Romney has devolved into political trench warfare. It is a close-quarters fight; Obama's operation, built over four years with more than a hundred offices around Ohio, and hundreds more living rooms, office basements and even garages set aside as Election Day "staging locations," versus the raw anger, worry and drive of a more recent set of Romney organizers.

At age 62 still as earnest as a college student, Edward O'Donnell is walking neighborhoods for Romney, driven by a growing panic that government debt is dragging the nation into bankruptcy. Like many here, "I have never been involved in an election campaign before," he said. But, "I committed months ago to doing anything and everything I can to try to change that direction."

The outcome rides largely on which campaign succeeds in getting its supporters to the polls by pestering, begging, calling, offering early voting instructions or Election Day buses, then pestering some more. It is a competition that has played out here with paid workers and volunteers in a strange universe of sleep deprivation, interminable door-to-door marches through cold rains, borrowed guest rooms and donated junk food.

In Cincinnati, the signs of the showdown are everywhere -- not just from the campaigns, but also from a vast array of groups that have descended on this place, knocking on the doors of residents so exhausted by all the knocks that one resident warded off more by posting an announcement on her front door that she had voted early and was, thank you very much, done.

The fight is bitter, with reports of yard signs stolen, run over and even set afire, political phone calls so endless that at least one man was answering his home telephone by barking "Romney" rather than hello, and tales of front-door confrontations ending in curse words or worse.

Publicly, at least, strategists on both sides here claim the edge.

The Obama campaign's extensive infrastructure is aimed at including as many volunteers as possible without forcing them to drive long distances to take part, a senior campaign adviser said.

"The whole goal is to allow for everyone who wants to help us to go communicate to voters who are likely to vote for the president in every corner of the state," Aaron Pickrell, the adviser, said. "So that's the purpose -- it's not to have muscle and show that we have a bunch of offices."

The Romney campaign was dismissive.

"There are places in the state where we don't have bricks and mortar," said Scott Jennings, a Louisville public relations executive who directs Romney field operations in Ohio. "But I didn't set out to build a campaign structure that had as its core function rent payments."