The Democratic Congressional Campaign Committee's independent expenditure arm has made a $730,000 television ad reservation in Wisconsin's 8th District for October.
In April, House Majority PAC reserved $220,000 in TV time for the final stretch of the 2016 campaign in the same Green Bay media market.
The DCCC's IE reservation brings the total in Democratic reservations in the district to at least $950,000.
The money the party is putting into this district underscores the importance Democrats are placing on this open seat to help them retake seats in the House.
Democrats are excited about their likely 8th District nominee, Outagamie County Executive Tom Nelson, who announced his candidacy in April.
"It's clear that Wisconsin's 8th district is one of the most competitive in the nation. Tom's record of public service and his decades of commitment to Northeast Wisconsin place this seat firmly in play," said Nelson campaign manager Ethan Susseles.
The district's current representative, Republican Reid Ribble, is retiring at the end of this Congress .
Ribble won his Green Bay-area seat with 65 percent of the vote in 2014.
But as a swing seat at the presidential level, Wisconsin's 8th District is the kind of seat Democrats need to contest if the party is going to win control of the House. President Barack Obama won the 8th District, under its current borders, by 9 points in 2008, and Mitt Romney carried it by 3 points in 2012.