WASHINGTON _ Be careful what you leave lying around the Capitol.

On Monday, a Democratic operative discovered the script of an upcoming online advertisement from Rob Portman's GOP Senate campaign.

The one-page document, which included the logo for the GOP political strategy firm FP1 Strategies, was found lying on a bench near the Ohio Clock outside the Senate, according to a source with knowledge of the situation.

The source provided a copy of the script to Roll Call.

Titled "Shameful," it includes a breakdown of the video and audio portion of the ad, which responds to recent attacks against the Ohio Republican's trade record.

Ohio Democratic Senate nominee Ted Strickland and allies like the Senate Majority PAC have criticized Portman over his past support for trade deals, part of a lively back-and-forth between the two sides over who better represents the interest of the state's large working-class voting bloc.

"Harry Reid and his out-of-state big money Super PAC know that Ted Strickland has a terrible record on China and jobs," the script instructs a narrator to say.

The ad has yet to be released by the Portman campaign, which confirmed the script's authenticity. A spokeswoman retorted that Strickland's own trade record is the greater liability in the race.

"We appreciate the sneak peek of our upcoming web ad and we stand behind every word of it," said Portman spokeswoman Michawn Rich. "It is shameful that Ted Strickland's record on China is so bad that outside special interest groups are having to spend millions of dollars in false advertising on behalf of his Retread candidacy."

The Strickland campaign used the revelation of the script to bash Portman's trade record again.

"Senator Portman has an unabashed, decades long record of voting for unfair trade deals that have outsourced hundreds of thousands of Ohio jobs to places like China _ and now his team is panicking," said Strickland spokesman David Bergstein, Strickland campaign spokesman.

Bergstein said that The Columbus Dispatch recently wrote that Portman and Strickland have "polar opposite" records on trade.

"While Ted has consistently voted against job killing trade deals, the only time Portman has stood up to China is when he got out of his chair to cut trade deals with them," he said.

The Portman-Strickland matchup is one of the year's most competitive Senate races. Polls indicate the two men are locked in a dead heat.