How did our legislatures become so divided by party?

In Congress today, there is a broad ideological “no man’s land” separating the two political parties today. The issue distance between them is perhaps as broad as it has ever been.  Congressional polarization is one of the most important American political trends of recent decades.

This polarization very much afflicts Minnesota. Voting patterns of the state’s US House members are often sharply polarized and the number of bipartisan votes at the Minnesota state capitol is very low.  The dramatically contrasting 2015 priorities distinguishing Minnesota House GOPers from State Senate Democrats are ample evidence of polarization.

What brought about the ideological sorting of the two parties? Though no single change or event can explain the rise of ideologically rigid parties, political scientists do agree on some of the contributing factors.

In the Democratic Party, its national ideological diversity was very much an artifact of Reconstruction era politics. Though the party was home to a growing number of moderate to liberal voters in the northeast, it had long been dominated by conservative Southern Democrats. In the south, Republicans were long viewed as the party of the Civil War and Reconstruction.

When Republicans ended Reconstruction and withdrew federal troops from the south in the late 1870s conservative Democrats regained control. What emerged were the decades of Jim Crow, poll taxes, literacy tests, and white primaries all employed to deny African Americans political representation. For much of the time between the end of Reconstruction and the late 1960s, there was virtually no Republican presence in the south.

As liberal northern Democrats, along with liberal Democratic presidents John Kennedy and Lyndon Johnson, aggressively pursue civil rights legislation the politics of the south began to change. The Voting Rights Act of 1965 stripped away many of the impediments long placed before African Americans in the south.

As more African Americans registered and voted, conservative Democrats were defeated in primaries or retired and were replaced by more liberal Democrats. To counter the emergence of liberal Democrats, southern conservatives looked to the Republican Party and the number of conservative southern Republicans grew steadily.

The Democratic Party’s support of civil rights attracted the support of African Americans, who had escaped the south and migrated to urban centers in the north, as well as younger voters and better educated voters as well. Many of these voters supported other more liberal causes such and environmental protection and equal rights for women. The Democratic Party responded by adopting these issues in an effort to bolster party strength.

As the Republicans base shifted to more conservative southern voters, the party agenda became more conservative and Republicans found greater support among voters uncomfortable with the social changes associated with the Democratic Party. As the nature of each party’s voting coalition changed the parties changed as well.

As odd as may seem, the advent of air conditioning and suburban sprawl had an impact on the ideological development of the parties as well. Indoor air conditioning, which made the hot southern and southwestern summers bearable, facilitated a mass migration of Americans from the industrial areas of the Northeast and Midwest.

These Americans tended to be older, white, and conservative. Political scientists Morris Fiorina and Samuel Abrams note that a significant number of Electoral Votes and seats in the House of Representatives followed these voters. In addition to migration to new regions of the country, voters began to spread out from the population centers, levels of civic engagement declined.

In his book Bowling Alone, Robert Putnam documents the decline of membership in community groups like the Rotary Club, as well as decreased time spent with friends, neighbors, and family and a decline in voter turnout. In the absence of cohesive communities and general membership organizations it became more of a challenge for candidates and elected official to make contact with voters.

New methods for contacting and motivating members were needed. The rise of special interest groups, such as the National Rifle Association, the Sierra Club, and the National Organization for Women, offered one way to reach voters. Candidates could win the support of special interest groups and rely on group members for support. But special interest groups tend to be single issue groups (gun rights, environmental protection) and they preferred to support candidates who passionately endorsed their agenda – which was not a recipe for moderation. Such groups hold great sway in both Minnesota and national elections.

The manner in which legislative districts are drawn played a role as well, though political scientist disagree over the significance of that role. In most states – including Minnesota — the drawing of Congressional and state legislative districts lines is completed by elected officials such as the governor, the state legislature, or both.

The advent of advanced computer modeling and mapping allowed for the creation of districts that advantaged the party in charge of the process, a practice typically referred to as gerrymandering. Democrats could divide Republican areas among multiple Congressional and state legislative districts in an effort to minimize their voting power. Republicans could pack Democrats into one or a just a few districts to achieve the same goal.

The result of either approach being safe partisan districts. In the US House of Representatives today, it is estimated that only about 50-60 of the chamber’s 435 seats are actually competitive. The same holds for Minnesota’s legislature. In the 2014 elections, only about twenty of 134 State House seats were electorally competitive. In the absence of electoral competition there is little pressure on elected officials to seek moderation.

Primaries can contribute to ideologically polarized parties as well, regardless of gerrymandering. Since the early 1970s, primaries have become the most common way to nominate candidates for office. Though a candidate may be safe in the general election, they may face a serious challenge from within their own party during a primary. In most states, primaries are closed to all but registered members of the party holding the primary. As such, there is little motivation for a candidate to embrace moderation. Turnout is generally lower in primary elections and primary voters tend to prefer more ideologically extreme candidates. That has often been the case in Minnesota in recent years.

Given the many reasons for the onset of ideological polarization in the contemporary Congress and Minnesota state legislature, it is unlikely it will abate anytime soon. The “new normal” for our state and national legislatures is a harshly partisan one. (1065 words)

Steven Schier is Congdon Professor of Political Science at Carleton College in Northfield, Minnesota.