United States Senate Election in Wisconsin, 1958 (PJW)

The United States Senate Election in Wisconsin in 1958 was held on November 6, 1958. Republican moderate and state governor Walter J. Kohler Jr. defeated Democratic businessman and former state assemblyman William Proxmire. The election was part of the 1958 United States Congressional Elections.

The seat had remained vacant since the death of Joseph McCarthy in September 1957. The McCarthyite Republicans sought to defend their seat, while the moderate Republicans and Democrats saw the position as an opening to make inroads into the once solid McCarthyite Midwest.

The moderate Kohler defeated McCarthyite candidate Henry Maier in the Republican primaries, while Proxmire faced little opposition on the Democratic side. Both sides ran well-managed, amicable campaigns. The election concluded with Kohler earning a narrow victory. Proxmire, his third defeat in the decade, would return to politics in 1962, when he challenged and successful won the other Wisconsin senate seat.