In the new ad, CLF points to Lamb's opposition to the GOP tax-reform plan as proof that he'll "join Pelosi's liberal flock." It goes on to use Pelosi's recent comments labeling individual savings created by the plan as nothing but "crumbs," while boosting Republican state Rep. Rick Saccone.

"Conor Lamb — a Pelosi-following, high-taxing, big-spending liberal. We deserve better," the ad's narrator says as a video of a herd of sheep plays to land the metaphor.

"Veteran Rick Saccone supported your tax cut. Now Pennsylvania families are receiving bonuses and raises. Rick Saccone fights hard for working families."

CLF has had success during the 2017 special election cycle tying candidates to Pelosi no matter their stance on her leadership. And the group made it clear in a recent memo that it will continue to bludgeon candidates by linking them to the Democratic leader, noting that its surveys of 69 competitive districts (including Pennsylvania's 18th District) show Pelosi's favorability underwater in every instance.

The ad is part of CLF's $1.5 million buy in the district, which is seeing a flurry of spending as Republicans look to shore up the deep-red district and Democrats position for an upset.

CLF and other GOP groups went up on the airwaves in the district early, but Lamb's campaign and the Democratic Congressional Campaign Committee responded this month with ad buys of their own, investments that show Democrats believe they have a shot in the district.

The National Republican Congressional Committee recently bought ad time in the district as well.