Pennsylvania Republican insiders expect the party will coalesce around Rep. Lou Barletta if and when the congressman announces his run for U.S. Senate.

But at least one of his rivals is signaling he doesn't intend to quietly step aside — and is taking a preemptive shot at the presumed favorite.

Jeff Bartos, a Montgomery County businessman, is launching a television ad Thursday that swipes at Barletta and attempts to turn some of the congressman's advantages — experience, name ID, and ties to the ultimate political outsider, President Trump — on their head.

"Career politicians make big promises but fail to deliver," the TV spot begins while showing images of Sen. Bob Casey, the Democratic incumbent, and then Barletta. "That's why Republicans need a fresh face — an outsider — to be our next senator."

The ad, set to air on Fox News, is unusual in that it comes before Barletta has even formally declared his intentions and as Bartos has significant work to do in introducing himself to voters. And while the spot is unlikely to be backed by big money (or widely viewed) this early in the race, it lays down a marker for Bartos' approach. A longtime GOP donor, he has never run for public office before and is little known outside of elite political circles.

"Lou Barletta must be doing something right, because it's clear that all potential opponents appear to be scared to death of him entering the Senate race," said Barletta spokesman Jon Anzur. "Lou Barletta is the only Republican who could beat Bob Casey, so it's understandable that other candidates are worried about him."

Pennsylvania Republicans widely expect Barletta to launch a run for Senate before Labor Day, and for several weeks his political aides have said an announcement is coming "soon."

Most of Bartos' ad goes on to talk about the candidate himself, describing him as "a principled conservative who will fight to repeal Obamacare and not give up," a shot at a GOP-controlled Congress that has failed to deliver on one of its signature promises.

Barletta voted for the GOP repeal plan to help it pass the House, only to see a repeal plan flop in the Senate. He has been one of Trump's most vocal boosters, which his supporters hope will help him in a state where the president pulled off a surprise victory.

Barletta is expected to be the favorite in a GOP primary that includes several other contenders vying to take on Casey next year.