FIRST ON FOX: The Senate Republican campaign committee didn’t wait long to take aim at Democratic Sen. Bob Casey of Pennsylvania.

One day after Casey announced his 2024 re-election campaign as he seeks a fourth six-year term representing the key general election battleground state on Capitol Hill, the National Republican Senatorial Committee (NRSC) launched a digital attack ad in a crucial Senate race that may determine if the GOP wins back the chamber’s majority next year.

Casey, a moderate who won his 2018 re-election by a comfortable 13-points during a blue-wave cycle, gave Democrats a big boost on Monday with his re-election announcement, as his party fights to retain their razor-thin 51-49 majority next year as they defend 23 of the 34 seats up for grabs. 

The senator, the son of a former two-term governor, is extremely well known in Pennsylvania. But Republicans view Casey, who turns 63 this week and is recovering from surgery to treat prostate cancer, as vulnerable. The NRSC on went up with a digital ad, shared first with Fox News on Tuesday, that labels the senator "shady" and spotlights what it claims are his connections to "scandal after scandal."

DEMOCRATIC SEN. BOB CASEY OF PENNSYLVANIA MAKES A BIG 2024 ANNOUNCEMENT

"Bob Casey keeps getting caught red-handed," the narrator in the spot charges. "Caught shelling out half a million dollars in campaign cash to his sister’s company. Caught peddling influence with his brother and caught breaking Congress’ insider trading law."

The half million dollars refers to a New York Post article from Monday that spotlights over $500,000 Casey has spent during his nearly three-decade campaign career on services from Universal Printing Company, which is owned by his older sister. 

The ad also refers to the senator’s brother Patrick Casey, who last year registered to lobby the Senate on numerous issues. The senator’s office told Politico earlier this year that their office abides by ethics rules that bar a lawmaker or their staff from having any lobbying contact with that lawmaker’s spouse or immediate family member who is a lobbyist.  The spot also refers to a report of Casey’s disclosure of a stock sale after a 45-day reporting window mandated by the Senate Ethics Office had expired.

The narrator in the ad also charges that Casey was "investing Pennsylvania pensions in a company backed by communist China, that the Department of Defense called ‘a national security threat.’"

Sen. Bob Casey of Pennsylvania at an event in Phialdelphia

Sen. Bob Casey, D-Pa., speaks before President Joe Biden about his infrastructure agenda while announcing funding to upgrade Philadelphia's water facilities and replace lead pipes, Friday, Feb. 3, 2023, at Belmont Water Treatment Center in Philadelphia. Casey said he’ll seek a fourth term, bringing unmatched name recognition in Pennsylvania politics to his party's defense of a seat in a presidential battleground state. ( AP Photo/Patrick Semansky, File)

The narrator is referring to an investment Casey supervised during his tenure from 2005 to 2007 as Pennsylvania treasurer of more than $31 million from state worker pensions into a Chinese government backed firm. A New York Post article late last month highlighted that "a state report on the fund from 2007 notes holdings by the Pennsylvania State Employees’ Retirement System in China Mobile Ltd. valued at $31,386,930 — the eighth-largest foreign asset held by the state at the time, joining a list that included major brands like Nestle, UBS and BP."

In 2020, the Department of Defense designated China Mobile as a national security threat, and a year later the New York Stock Exchange de-listed the company.

"This story is a false attack — the investment in question was made before Bob Casey became State Treasurer in 2005," a spokesperson for Casey told the New York Post.

"No one is tougher on China than Senator Casey. During his time in the Senate, he has fought to crack down on China’s currency manipulation, and against unfair trade practices and US corporations that invest in China at the expense of American workers," the spokesperson added.

In last November’s midterm elections, Democrats flipped Pennsylvania’s other Senate seat – which was held by retiring GOP Sen. Patrick Toomey - as now-Sen. John Fetterman edged Republican Mehmet Oz, the cardiac surgeon and celebrity doctor. 

WHAT REPUBLICAN DAVE MCCORMICK TOLD FOX NEWS ABOUT LAUNCHING A 2024 SENATE CAMPAIGN 

Republicans are aiming once again to try and flip a Senate seat in the Keystone state and the digital ad – which is backed by a modest five-figure buy – is likely just a small appetizer of more to come as the 2024 cycle heats up.

"Know this: [Senate Republican leader] Mitch McConnell and the GOP are already coming for this seat. I won’t be able to win this re-election fight alone," Casey warned supporters in a fundraising email on Monday. 

The senator, who had roughly $3 million cash on hand in his campaign coffers at the start of the year, will likely campaign for re-election by spotlighting that he’s delivered on bringing infrastructure spending and manufacturing jobs to Pennsylvania. He’s not expected to face any serious primary challenge for the Democratic Senate nomination.

The NRSC is courting Dave McCormick to take on Casey. McCormick, a former hedge fund executive, West Point graduate, Gulf War combat veteran and Treasury Department official in former President George W. Bush’s administration, narrowly lost to Oz in last year’s GOP Senate primary by less than 1,000 votes.

McCormick, who’s currently on a tour for his new book "Superpower in Peril: A Battle Plan to Renew America," told Fox News last month that "in terms of the Senate, we’re going to get through this book tour and it’s a big decision. It’s not one we feel like we have to make right now. And we’ll be thinking about it as a family and praying about it."

CLICK HERE TO GET THE FOX NEWS APP 

McCormick isn’t the only Republican considering a Senate run in Pennsylvania next year.

Former state Sen. Doug Mastriano, a far-right Trump loyalist who lost last year’s gubernatorial election by double digits, is also mulling a bid, and he’s already taken shots at McCormick.

"For months, Pennsylvania Republicans savaged McCormick over his record of outsourcing jobs and for his close ties to China, Wall Street and Mitch McConnell. With Mastriano making noises about entering the race, Republicans’ Senate primary dynamics are getting messier by the day," Democratic Senatorial Campaign Committee spokesperson David Berstein told Fox News.