The pending retirement of Rep. Ken Buck (R-CO), announced Tuesday, will slim even further the already dwindling Republican majority in the House of Representatives and make it even more difficult for the party to pass legislation.

Buck’s retirement will vacate a fourth seat that was held by Republicans when the 118th Congress convened in January 2023. Since then, one member, former Rep. George Santos, a Republican, was expelled from office and replaced by Rep. Tom Suozzi (D-NY). Two others, former Reps. Bill Johnson and Kevin McCarthy resigned and have yet to be replaced in special elections.