The largest outside conservative spenders on House races are rolling out nearly $4 million in new spending in five congressional districts.

The new spending, shared first with Roll Call, brings the total spending for the Congressional Leadership Fund, the super PAC tied to House Republican leadership, and its sister nonprofit advocacy organization, American Action Network, to twice what the two groups spent in 2014 combined. 

The groups are spending more than $40 million in 32 districts, with additional spending to be announced in the coming days. Both organizations are helping set up a GOP firewall by investing in second-tier races to protect the GOP majority and allow the National Republican Congressional Committee to free up resources to spend on its most competitive races. 

Kansas’ 3rd District: One of those second-tier races is in Kansas where GOP Rep. Kevin Yoder is facing a challenge from Democratic nominee Jay Sidie. The Congressional Leadership Fund is announcing $800,000 for broadcast, cable TV and digital advertising in the Kansas City media market for the final two weeks of the campaign. The Democratic Congressional Campaign Committee recently announced a $1.1 million reservation in the Kansas City suburbs. 

Minnesota’s 8th District: Both organizations are spending more in this district than in any other race in the country. The fund is spending an additional $2.3 million for broadcast, cable and digital advertising in the Minneapolis-St. Paul and Duluth media markets during the final two weeks of the election. That brings its total spending here to $4.5 million. 

Republican businessman Stewart Mills is taking a second shot at unseating Democratic Rep. Rick Nolan in this Iron Range district, which is more friendly to GOP presidential nominee Donald Trump than other Democratic districts. It’s one of the Republicans’ few pickup opportunities this cycle, and it’s a district that’s particularly important to these conservative groups since their founder, former Sen. Norm Coleman, is from Minnesota. 

Florida’s 18th District: The Congressional Leadership Fund will spend an additional $500,000 on broadcast and cable TV advertising in the West Palm Beach media market. This district is another pickup opportunity for Republicans, and one that they feel good about with their nominee Brian Mast. The new spending brings the fund’s total investment here to $3.1 million — it second-highest investment in the country. 

Iowa’s 1st District: American Action Network is spending an additional $190,00 on TV and digital ads in the Cedar Rapids media market during the final two weeks of the election. Its total spending in the district will now be $440,000.

Freshman Rep. Rod Blum is a member of the House Freedom Caucus and has had a tenuous relationship with GOP leadership. He’s fending off a challenge from Democrat Monica Vernon in a district that President Barack Obama twice carried by double digits. But Trump’s relative popularity in the district — at least before the revelation of a 2005 tape in which he bragged about groping women — pushed Blum from No. 2 to No. 9 on Roll Call’s most vulnerable House members list. 

Wisconsin’s 8th District: The Congressional Leadership Fund is spending an additional $100,000 on TV in the Green Bay media market during the final two weeks of the election, bringing its total spending here to $900,000. Republicans are trying to keep this open seat in GOP hands with Mike Gallagher, who’s facing Democrat Tom Nelson. Democrats recently cut some of their spending here, and The Rothenberg & Gonzales Political Report/Roll Call moved the race from Tossup to Leans Republican.