If Republican Dave McCormick gets his way, the phrase “Biden and Bob Casey” will be as familiar to Pennsylvania voters as “Sonny and Cher” or “Turner and Hooch.”

In his speech to the Republican National Convention Tuesday night (he’s the only Pennsylvania Republican scheduled to speak at the RNC), McCormick repeatedly invoked the “failed policies of Biden and Bob Casey” on immigration, inflation and crime.

“Biden and Casey’s failed policies have crushed working families with sky-high prices for gas and groceries and rent and regulations to kill Pennsylvania natural gas under President Trump,” McCormick told the Milwaukee crowd.

It’s not a subtle political strategy: Democratic President Joe Biden’s polls are bad — and getting worse — among Pennsylvania voters. In the RealClearPolitics polling average, Biden has trailed Trump for all of 2024, and he’s currently behind 39.5 to 43.1 percent. Those polls were almost entirely taken before the failed assassination attempt targeting Trump in Butler, Pa. on Saturday.

And a new national poll shows 70 percent of Americans (including 65 percent of Democrats) want Biden off the ticket.

So, tying three-term Democrat incumbent Casey to his party’s troubled presidential nominee makes political sense for the GOP. In addition to his stump speech rhetoric, McCormick is running ads claiming Bob Casey is “Ridin’ With Biden.”

Casey is doing his part to help, greeting Biden at the Philadelphia airport last week and campaigning with him at a Black church in the city. While other Democrats are decrying Biden’s decision to remain in the race — prominent California Rep. Adam Schiff urged Biden to drop out on Wednesday — Casey is still backing Biden.

“I’ve been at this a while, and I know his work,” Casey said immediately after Biden’s disastrous debate performance on June 27.

But asked about the impact of the presidential race on his reelection bid during a Harrisburg, Pa. press conference on Wednesday, Casey was more circumspect.

“I’m a United States senator. I got a job to do and I’m a candidate for reelection,” Casey said. “And so what I’m going to do for the next three and a half months, and the time I’m a candidate, is to make sure that I make very clear the contrast between me and my opponent.”

So far, so good, based on the polling. A New York Times/Siena College poll released Monday found Trump beating Biden 48 to 44 percent, for example, while Casey led McCormick 50 to 39 percent. McCormick has consistently trailed Casey, but political professionals say a rising Trump tide could lift all GOP boats.

However, Pennsylvania Democratic operative J.J. Balaban told NBC News he doesn’t believe Casey will be hurt by Biden.

“He has a pretty established brand in a state that is big enough that it’s tough to get known,” Balaban said. “So he’s probably not worried about having to prove that he’s independent of Joe Biden.”

But another veteran Democratic strategist isn’t so sure.

“The strategy is pretty common and makes a lot of sense,” said T.J. Rooney. “McCormick is particularly advantaged at the moment considering no president has ever been this unpopular, this close to an election.”