The Capitol changed little during this period, but not for lack of trying. The most dramatic proposal was for an addition to the east front, intended to provide a better sense of support for the dome and to add more rooms. Thomas Walter floated the idea in 1863; Speaker Joseph Cannon revived it in 1904. The idea surfaced again between 1935 and 1937, winning Senate support. The House defeated it—though an extension finally was built, from 1958 to 1962.

There were other suggestions as well. In 1924, some senators advocated rebuilding their chamber along an outside wall to give the room windows for natural light and fresh air. (Many blamed the lack of fresh air for the failing health of a few senators.) This idea gained support—until 1929, when air-conditioning silenced the complaints.