Three U.S. states originally had unicameral legislatures, Pennsylvania, Georgia, and Vermont. Unicameralism didn’t last long in those states. Georgia adopted a second chamber in 1789. Pennsylvania in 1790. Vermont held out a bit longer, adding a second chamber to its legislature in 1836. All states subsequently joining the Union, including Nebraska, came into it with bicameral legislatures.

Interest in unicameralism returned, however, with the advent of the Progressive movement but in new ways.

Between 1912 and 1920, around a third of U.S. states considered adopting legislative unicameralism in some serious capacity. Constitutional proposals in a handful of states reached the stage for a popular vote. Oregon voters rejected unicameralism in 1912 by a margin of greater than two to one, as did Arizona voters in 1915. A 1914 unicameral proposal in Oklahoma received fifty-eight percent approval among those who cast ballots on the proposal, 99,686 supporting the reform against 71,742 opposing. The proposal failed, however, because the state required constitutional proposals to receive a majority of votes cast overall in the election, not merely a majority of the votes cast on a proposal: Over 75,000 voters in that election skipped voting on the unicameral proposal, so it received express endorsement from only 40 percent of Oklahoma voters who cast ballots in that election.

Nationwide interest in unicameralism pretty much died off by the time Nebraskans adopted the measure in 1934. Nebraska’s well-known Progressive Senator, George Norris, threw himself personally into the campaign that year. While largely forgotten outside of Nebraska today, Norris was a Progressive powerhouse both inside and outside the state during that period.

But why the resurgence of interest in unicameralism during the latter part of the Progressive era? In one sense it’s not a surprise, given the era’s increased populism and interest in more-transparent, simpler, politics, and its corresponding hostility to checks and balances as unnecessarily deterring the adoption of needed legislation.

Part and parcel with this, however, were three state-level constitutional changes in prior decades that undermined the perceived need for continued check and balance of second legislative chambers: the rise of heightened judicial review for ordinary legislation (a.k.a., the doctrine of substantive due process), the rise of the direct democracy in many (although not all) states, and the spread of the executive veto. James Mathews, for example, writing in a 1912 edition of the American Political Science Review, observed that there has been a “general movement . . . in the transfer of legislative power from the legislatures to the courts, to the people, and to the governor.”

The transfer of legislative power to the people is obvious enough, the states, particularly in America’s West, adopted the initiative and referenda options for their Constitutions. This provided legislative power directly to the people in the form of the initiative, and provided a direct veto on legislation adopted by legislatures in the form of the referendum. Legislative power transferred to governors refers of course to the veto (or, more accurately, to the partial veto). Most state governors did not have this power early in the country’s history, but the practice spread gradually throughout the states prior to and just after the Civil War. (Although North Carolina granted its governor the veto power only 21 years ago, in 1996.)

The “transfer of legislative power from the legislatures to the courts” does not refer to the power of judicial review as we know it today. Recall that the early 20^th Century was the period of robust application by judges of “substantive due process.” Under this doctrine, judges employed the 14^th Amendment to accord heightened review to all legislation, not merely to laws that imposed on fundamental rights like speech or trenched on the rights of “insular and discrete” minority groups. This meant state governments bore the burden of affirmatively demonstrating that the laws legislature’s adopted were “reasonable” impositions on liberty.

James D. Barnett, in a 1915 article on “The Bicameral System in State Legislation” in the American Political Science Review observed,

Whatever the view which generally prevailed in the early days of our government as to the power of the courts to pass upon the constitutionality of the acts of the legislature, the vast possibilities of constitutional limitation could not have been then appreciated. The federal constitution in its original form placed various restricts upon the legislatures of the States, and amendments, particularly the fourteenth amendment, have added to these restrictions.

In a clear reference to the rise of substantive due process, Barnett adds, “The restrictions have marvelously grown at the hands of the courts.”

Barnett noted the impact this had on the need for second legislative chambers, “From the operation of all these limitations . . . the state legislatures is today certainly ‘little more than a shadow of its former self.’” The perception grew during this period that second chambers were not as necessary in U.S. states to the production of good legislation as they were earlier in American history. Or, perhaps more carefully, the perception grew that the benefits generated by second legislative chambers were no longer worth the cost of maintaining those chambers. And, yes, the cost of second chambers figured prominently in unicameral campaigns in Oregon and Nebraska. Notably, the one successful campaign to adopt unicameralism, in Nebraska, came in the midst of the Great Depression in 1934. George Norris consistently mentioned costs savings when campaigning for the reform.

The development of other institutional forms in the states, the veto, direct democracy, and activist judicial review (albeit, conservative activism) apparently affected the perceived need for second legislative chambers, and spurred part of the interest in unicameralism during this era.

One implication of this development continues today, albeit limited to Nebraska: A crucial part of the argument for the nonnecessity of second chambers during the Progressive era derived from the heightened review of legislation of ordinary legislation provided by courts applying substantive due process doctrines. Federal courts and most states courts gradually turned against substantive due process from the late 1930s onward, replacing the doctrine’s heightened review of ordinary socio-economic legislation with highly deferential rationality review. Courts in Nebraska followed suit. But note, if Nebraska eliminated its second legislative chamber in significant part because of heightened judicial review provided by courts applying the doctrine of substantive due process, then courts would not be similarly justified in following bicameral states, or the bicameral national government, in adopting deferential rationality review for legislation. Deferential rationality review would be institutionally unjustified in unicameral Nebraska relative to the bicameral states.