Senate Mullin departure creates ‘House whisperer’ vacancy for Senate GOP by Al Weaver - 03/12/26 6:00 AM ET by Al Weaver - 03/12/26 6:00 AM ET Share ✕ LinkedIn LinkedIn Email Email NOW PLAYING Sen. Markwayne Mullin’s (R-Okla.) pending departure from the upper chamber to lead the Department of Homeland Security is creating a vacancy that Republicans wonder if they’ll be able to fill: Unofficial liaison to the House. It’s an informal role, and one that didn’t truly exist prior to Mullin arriving. But the Oklahoma Republican has been a key player for the Senate GOP since he entered the chamber three years ago emerging as a top ally of Senate Majority Leader John Thune (R-S.D.) and turning into a source of power in his own right.  Much of that was due to his relationships across the Capitol complex, developed during his five terms in the House and now put to use to maintain bicameral harmony. And with key legislative items potentially coming down the line in the coming months, Senate Republicans believe the lack of his presence will be felt. “People outside of D.C. think the north side of the building and the south side of the building talk to each other all the time and … that’s not true,” said Sen. James Lankford (R-Okla.), who previously served in the House. “It’s hard to be able to maintain relationships across the building because our schedules are different, we function different, the structure of how we actually operate is so different.”  “Markwayne had really good relationships in the House and the Senate, and that’s going to be tough,” Lankford continued, also noting his close relationships with the White House and across the upper chamber. “It’ll be a loss for the Senate for him going into this position, but it’ll be a gain for the country for him to be able to do it.” President Trump’s decision to fire outgoing Homeland Security Secretary Kristi Noem and replace her with Mullin caps a quick ascent for the Oklahoma Republican. On top of Mullin’s relationships with Trump and Thune — having served as his most public supporter during his leadership run — he also has close proximity to Vice President Vance, having entered the Senate with him in 2022. He also counts Sens. John Barrasso (R-Wyo.) and Susan Collins (R-Maine) as allies as he serves on the whip team and was recruited to the Appropriations Committee last year, respectively.  But lawmakers have often noted that his ability to communicate with the House has been among the biggest things he brought to the table. Some in the Senate GOP conference have even dubbed him the “House whisperer” and believe he has been integral to the party’s workings in recent years.  “He’s a pretty valuable resource that way,” said Sen. Kevin Cramer (R-N.D.), who entered the House alongside Mullin in 2012, noting that he’s been wondering how that void gets filled in recent days. “[H]e is just sort of exceptional in the sense that he’s ambitions. … He loves being in the mix. He’s gregarious in his personality, bold in his presentation.” Mullin was a frequent attendee at House GOP conference meetings throughout his Senate tenure, and routinely communicated the state of play and other dynamics to Republican leaders.  Most notably, he was the lead Senate GOP negotiator with House Republicans from high-tax states in search of a resolution on a cap for state and local taxes (SALT). The hard-won SALT deal was one of the keys to unlocking President Trump’s “big, beautiful bill.” He also served as a conduit during a battle between the chambers over whether to enact Trump’s priorities in one massive reconciliation bill or two packages, having arranged a meeting between Thune and House Ways and Means Chairman Jason Smith (R-Mo.) — Mullin’s roommate.  Senators past and present have noted that prior to Mullin, there simply was nobody taking on a similar role despite a significant number of senators previously serving across the Capitol complex. Nearly two dozen current Senate Republicans were House members at one point in time.  “I know it sounds kind of crazy, but people weren’t doing that before him,” former Sen. Kyrsten Sinema (I-Ariz.) — a longtime friend and former House colleague — told The Hill about his informal role, saying that Mullin has strong relationships with “different subgroups” within the conference that have paid off.  There also isn’t an obvious person to backfill the job. Senate Republicans have indicated they expect it to be a team effort.  “Nobody’s going to be able to do what he’s done,” said Sen. Katie Britt (R-Ala.), a friend of Mullin. “We have a number of members who have great relationships in the House. I think that they will, obviously, elevate those. … It’ll take a lot of people to fill the role of one person, and because it’s not just one person, there’s a connectivity issue there.” Some even have joked that Mullin may continue to do that work despite his move into the ad