Democratic Congressional Campaign Committee Chairman Ben Ray Luján expressed confidence Thursday his party will take control of the House, but he remains concerned about the impact of outside Republican money and gerrymandered districts.

“As far as what keeps me up at night, Republicans have committed what seems like unlimited amounts of money to these elections,” the New Mexico Democrat told reporters Thursday. “We’re seeing Super PAC after Super PAC on the Republican side continue to tear in.”

Luján said the other challenge for Democrats involves congressional maps drawn to favor Republicans — a concern shared by his predecessor, former New York Democratic Rep. Steve Israel.

Luján said his party is still in a strong position for a net gain of 23 seats to take over the House, pointing to candidates with compelling personal profiles who are connecting with voters.

The main Republican Super PAC focused on House races, the Congressional Leadership Fund, has reported record fundraising totals this election cycle. The group launched television ads in a slew of competitive districts starting in early August in an effort to define first-time Democratic candidates early on in the general election campaign.