After Sen. Jeanne Shaheen’s decision against making another run for U.S. Senate in 2026, potential contenders are beginning to emerge."I've already gotten a call from somebody in Washington said that it's going to be the premier U.S. Senate race in the country," New Hampshire Democratic Party Chairman Ray Buckley said.Democrats and Republicans are already weighing whether to run for the open seat. Sources close to Reps. Chris Pappas and Maggie Goodlander told WMUR that both Democrats are considering running for U.S. Senate."I think both of them are doing an incredible job. in Washington already. Either one would be terrific U.S. senators," Buckley said.Pappas won a third term in Congress after defeating Republican Russell Prescott by about 8 points in the 1st Congressional District.>> VIDEO: Watch Shaheen's full announcementGoodlander, meanwhile, is early in her first term representing the 2nd Congressional District after she beat Republican Lily Tang Willaims by more than 5 points in the general election.“The definition of a House member is someone who wants to be in the U.S. Senate. The U.S. Senate, of course, is the best club in the world. That’s what they call it,” Neil Levesque with the New Hampshire Institute of Politics said. “So, it’s not surprising that these two Democrats are looking at it. This could be wide open and quite a primary if they do both run for U.S. Senate.”>> Subscribe to WMUR's YouTube channel | Sign up for the WMUR Politics Newsletter <<As for the Republican side, Scott Brown, who served as a U.S. senator for Massachusetts from 2010 to 2013 and lost his bid for U.S. Senate in New Hampshire in 2014, told WMUR in December he was weighing whether to get in the race for 2026.Brown also posted about Shaheen’s decision on X.“I appreciate @jeanneshaheen’s service to our state and for her support and vote for me as NH’s Ambassador to NZ and Samoa. Now it’s time for New Hampshire to have someone in the delegation who fights for our priorities and stands with, not against, the Trump agenda,” Brown wrote.>> Timeline: Key moments from Shaheen's career:Another big name is former Gov. Chris Sununu, who on Tuesday night told the Washington Times he hasn’t ruled out a run for U.S. Senate. He said that President Donald Trump’s focus on making the federal government more efficient has made him give running for the U.S. Senate more thought. >> Download the free WMUR app to get updates on the go: Apple | Google Play <<Sununu previously considered a U.S. Senate run in 2022 but ultimately decided to run again for governor. Tang Williams, meanwhile, told WMUR she wouldn't rule out a run for U.S. Senate. The race could have a significant impact on the balance of power in the U.S. Senate in 2026. Republicans will be looking to flip a seat that, by the end of Shaheen’s term, will have been in Democratic control for 18 years.“The Republicans nationally and the Democrats nationally want to keep this seat. Remember that the Trump administration has the ability to raise a lot of money because he’s the president, but also Democrats have held this seat for a long time,” Levesque said. “I think nationally, the real money, the big money will come into New Hampshire because it is a seat that’s not guaranteed to one party or the other.”"This is a two-year race. It'll probably be one of the most expensive races ever in New Hampshire history," Levesque said.New Hampshire Republican Party Chairman Jim MacEachern released the following statement regarding Shaheen's decision:"Last November, Granite Staters overwhelmingly showed support for strong Republican leadership. Governor Kelly Ayotte and Republicans in Concord are delivering on their promises and making our state Safe, Prosperous and Free," MacEachern said. "It's clear that Senator Shaheen's retirement will produce a Democrat primary filled with liberal politicians who would raise taxes, increase government regulation, and make our communities less safe. Voters rejected this nonsense last November, and they will again in 2026."