JANESVILLE, Wis. – Rob Zerban spent his morning on his hands and knees scrubbing a toilet in a homeless shelter. Half a country away, Paul Ryan stood under a spotlight in Virginia talking about why he should be the next vice president.

So it goes in Zerban’s longshot bid to seize the House seat Ryan has held for 14 years. While the Republican vice presidential hopeful has jetted around the country touting Mitt Romney, the Kenosha Democrat has been getting his hands dirty in southern Wisconsin’s 1st Congressional District.

Most challengers face uphill battles against established incumbents, but Zerban’s predicament is especially tough: He’s essentially battling a phantom.