This graph shows an interesting feature of Oregon politics during the 1930s. The Republican nominee narrowly won the district in 1934, 1938, and 1940.
This graph also shows the Republican recovery in Oregon starting with the 1938 election that persisted through the 1940s.
During the period 1930 through 1940, Oregon’s 3rd Congressional District boundary followed the Multnomah County boundary.
Source: Oregon Secretary of State.