A pair of outside groups focused on helping the Republican Party in the House of Representatives has hired the engineer of one of the most successful Senate reelection campaigns in 2016 to work on keeping the GOP majority during Donald Trump’s presidency.

The American Action Network and its sister super PAC, the Congressional Leadership Fund, announced Monday that Corry Bliss will be the executive director of both organizations. Bliss ran this year’s reelection of Sen. Rob Portman (R-Ohio), a victory that was widely seen as one of the strongest and most successful Senate Republican campaigns of the 2016 cycle.

Despite trailing former Ohio governor Ted Strickland (D) in the polls early on, Portman ended up winning by 21 points, outperforming Trump in the state by an impressive seven percentage points. By October, Portman had run up such a large advantage over Strickland that Senate Republicans were able to divert their resources elsewhere, a break many Senate GOP operatives credited with helping them keep their majority despite sometimes long odds. Bliss also engineered a come-from-behind victory in 2014 with Sen. Pat Roberts’s victory in Kansas over independent Greg Orman.

Bliss’s hiring to two of the biggest outside-group players in House races suggests that Republicans are not taking their majority in Congress for granted and that they are girding for a fight in the 2018 midterms. History indicates voters typically punish the party in power more often than the party out of it; Democrats lost more than 60 House seats during the Obama administration. Republicans will start 2017 with a 241-194 majority.

Republican operatives praised the news.

“This is an extremely good selection,” said Josh Holmes, the former chief of staff for Senate Majority Leader Mitch McConnell (R-Ky.) and a current Senate Republican strategist. “And this tells me that everybody’s being very serious at the outset about defending our majorities.”

Norm Coleman, once a senator from Minnesota, co-founded the American Action Network, a nonprofit group focused on center-right public policy, in 2010 with George H.W. Bush aide Fred Malek. Its more overtly political sister super PAC, the Congressional Leadership Fund, was founded soon after.

Together, the two groups have poured tens of millions of dollars into House races. In 2016, they spent more than $48 million on dozens of contests. Of the 39 candidates backed by CLF in 2016, all but three won.

“I’m deeply honored to have the opportunity to join Senator Coleman, Fred Malek, and the exceptional team at AAN and I look forward to defending the House majority over the next two years,” Bliss told The Washington Post in a statement.