HARRISBURG — Republican Senate candidate Lou Barletta began airing his first TV attack ad Friday, accusing two-term Democratic Sen. Bob Casey of being ineffective, lazy and asleep on the job. Casey’s campaign countered that Barletta is lying about the incumbent’s record.

The ad, running on cable in Philadelphia and on broadcast TV in every other Pennsylvania market except for Casey’s hometown of Scranton, pastes photos of Casey’s head, with his eyes closed and lips moving slightly to snore, on a suit-wearing man slumped and sleeping in various office settings.

“You know them, the do-nothings, the lazy ones, the slackers,” the narrator says. “Yet somehow they still grab a paycheck like Bob Casey. For decades, Casey’s been sleeping on the job, writing almost no legislation and rated one of the least effective senators. Twice.”

Barletta, a four-term Republican congressman and one of President Donald Trump’s biggest allies on Capitol Hill, has badly lagged Casey in fundraising. No independent poll puts him within striking distance, making it a low-profile race in a state Trump won in 2016.

Barletta’s TV ad is starting as former President Barack Obama comes to Philadelphia to stump for Casey, who is seeking a third term in the Nov. 6 election.

Barletta’s campaign pins its claim of Casey’s lackluster record of success on congressional records showing that only four Casey bills have become law and a methodology from the University of Virginia’s Center for Effective Lawmaking of Casey’s legislative performance from 2007 to 2010. That’s when Casey was ranked among the bottom half of Democratic senators in effectiveness.

However, Casey’s ratings have substantially improved since then, putting him in the top third of Democratic senators in 2011-12, in the top half in 2013-14 and in the top fifth in 2015-16, the last complete two-year session of Congress.

“After nearly a decade in Washington, Lou Barletta is resorting to lies because he can’t defend his record of voting to slash Medicare and end protections for preexisting conditions,” Casey’s campaign said.

Elizabeth Sherman, an assistant professor of American politics at American University in Washington, D.C., said it isn’t an accurate measure of a legislator’s success to simply count how many of their bills became law without taking into consideration legislative process and politics.

“A big bill with Casey’s name on it doesn’t stand a chance in the Republican-dominated Senate and House, but that doesn’t mean he doesn’t have a record of performance in making steady progress,” Sherman said.