Democrat Conor Lamb, a former U.S. attorney and U.S. Marine Corps veteran running to represent Pennsylvania’s 18th Congressional District, speaks to an audience at American Legion Post 902 on Jan. 13 in Houston, Pa. (Jeff Swensen/Getty Images)

The Congressional Leadership Fund, a super PAC closely aligned with House Speaker Paul D. Ryan (R), is putting $1.5 million into TV ads ahead of the March 13 special election in Pennsylvania’s 18th Congressional District. The ad buy, which will start Friday, comes two weeks after the CLF opened two campaign offices in the southwestern Pennsylvania district.

“We will attack Conor Lamb, we will define Conor Lamb,” said Corry Bliss, the CLF’s executive director, referring to the Democratic nominee who has made the election closer than Republicans would like. “And we will explain to voters in Pennsylvania’s 18th district that Conor Lamb would be nothing more than a rubber stamp for Nancy Pelosi’s liberal agenda.”

Super PACs have already crowded the airwaves in the 18th, with both Ending Spending and the 45Committee — pro-Trump super PACs supported by Chicago Cubs owner Joe Ricketts — buying ads to attack Lamb and boost Republican nominee Rick Saccone. Both candidates are veterans, and both were nominated by party activists in hotly contested conventions.

But Lamb, 33, a former assistant U.S. attorney whose family is well known in local Democratic politics, has rattled Republicans more than Saccone has rattled Democrats. The 59-year-old Republican, who has a loyal base in his state legislative district, has never raised much money for his campaigns. On labor and economic issues, he’s significantly to the right of former congressman Tim Murphy, whose resignation triggered the election but who had usually gotten the backing of local unions — unions which claim tens of thousands of members in the district, and now back Lamb.

National Democratic groups have been quieter about the race, similar to the approach they took for much of the runoff in Alabama’s 2017 special Senate election. (Late in that race, Democrats created a super PAC to help eventual winner Doug Jones.) Lamb has tried to turn the lack of Democratic air cover into an advantage, mocking the large donors behind the super PACs — the Cubs are not especially popular in Pirates country — and highlighting polls that show a close race.

On Tuesday, Lamb also launched his second TV spot — the first ad in the race to mention the government shutdown. After a veteran is shown telling Lamb that the divisions in Washington are “ridiculous,” Lamb says that “in the military, as you know, when you don’t get the job done, you get relieved.”

Democrat and former Marine Conor Lamb released an ad to promote his candidacy in the March 13 special election to represent Pennsylvania's 18th Congressional District. (Conor Lamb)

It’s a not-so-subtle reference to Lamb saying that he will not support House Democratic Leader Nancy Pelosi if he gets to Congress, making him the latest in a string of red-district Democrats to suggest that the party needs a new candidate for speaker of the House. Lamb’s promise has not changed Republican messaging about the race, as shown by the CLF’s plans to tie him to Pelosi. (The 45Committee’s ad also ties Lamb to Pelosi.)

Democrats also think that the end of the shutdown will be a positive for Lamb. Mike Mikus, a local Democratic strategist who is not working on Lamb’s campaign, said that the shutdown potentially played poorly in the district, especially if its cause was not explained.

“I’m sure a majority support dreamers but there is very [little] personal connection to the issue because of the tiny immigrant community,” Mikus said.