Once you control for region, it turns out that Democrats were actually more likely to support the 1964 Civil Rights Act

With Republicans having trouble with minorities, some like to point out that the party has a long history of standing up for civil rights compared to Democrats. Democrats, for example, were less likely to vote for the civil rights bills of the 1950s and 1960s. Democrats were more likely to filibuster. Yet, a closer look at the voting coalitions suggests a more complicated picture that ultimately explains why Republicans are not viewed as the party of civil rights.

Let's use the 1964 Civil Rights Act as our focal point. It was arguably the most important of the many civil rights bills passed in the middle part of the 20th century. It outlawed many types of racial and sexual discrimination, including access to hotels, restaurants, and theaters. In the words of Vice President Biden, it was a big "f-ing deal".

When we look at the party vote in both houses of Congress, it fits the historical pattern. Republicans are more in favor of the bill:

80% of Republicans in the House and Senate voted for the bill. Less than 70% of Democrats did. Indeed, Minority Leader Republican Everett Dirksen led the fight to end the filibuster. Meanwhile, Democrats such as Richard Russell of Georgia and Strom Thurmond of South Carolina tried as hard as they could to sustain a filibuster.

Of course, it was also Democrats who helped usher the bill through the House, Senate, and ultimately a Democratic president who signed it into law. The bill wouldn't have passed without the support of Majority Leader Mike Mansfield of Montana, a Democrat. Majority Whip Hubert Humphrey, who basically split the Democratic party in two with his 1948 Democratic National Convention speech calling for equal rights for all, kept tabs on individual members to ensure the bill had the numbers to overcome the filibuster.

Put another way, party affiliation seems to be somewhat predictive, but something seems to be missing. So, what factor did best predicting voting?

You don't need to know too much history to understand that the South from the civil war to the Civil Rights Act of 1964 tended to be opposed to minority rights. This factor was separate from party identification or ideology. We can easily control for this variable by breaking up the voting by those states that were part of the confederacy and those that were not.

You can see that geography was far more predictive of voting coalitions on the Civil Rights than party affiliation. What linked Dirksen and Mansfield was the fact that they weren't from the south. In fact, 90% of members of Congress from states (or territories) that were part of the Union voted in favor of the act, while less than 10% of members of Congress from the old Confederate states voted for it. This 80pt difference between regions is far greater than the 15pt difference between parties.

But what happens when we control for both party affiliation and region? As Sean Trende noted earlier this year, "sometimes relationships become apparent only after you control for other factors".

In this case, it becomes clear that Democrats in the north and the south were more likely to vote for the bill than Republicans in the north and south respectively. This difference in both houses is statistically significant with over 95% confidence. It just so happened southerners made up a larger percentage of the Democratic than Republican caucus, which created the initial impression than Republicans were more in favor of the act.

Nearly 100% of Union state Democrats supported the 1964 Civil Rights Act compared to 85% of Republicans. None of the southern Republicans voted for the bill, while a small percentage of southern Democrats did.

The same pattern holds true when looking at ideology instead of party affiliation. The folks over at Voteview.com, who created DW-nominate scores to measure the ideology of congressmen and senators, found that the more liberal a congressman or senator was the more likely he would vote for the Civil Rights Act of 1964, once one controlled for a factor closely linked to geography.

That's why Strom Thurmond left the Democratic party soon after the Civil Right Act passed. He recognized that of the two parties, it was the Republican party that was more hospitable to his message. The Republican candidate for president in 1964, Barry Goldwater, was one of the few non-Confederate state senators to vote against the bill. He carried his home state of Arizona and swept the deep southern states – a first for a Republican ever.

Now, it wasn't that the Civil Rights Act was what turned the South against the Democrats or minorities against Republicans. Those patterns, as Trende showed, had been developing for a while. It was, however, a manifestation of these growing coalitions. The South gradually became home to the conservative party, while the north became home to the liberal party.

Today, the transformation is nearly complete. President Obama carried only 18% of former Confederate states, while taking 62% of non-Confederate states in 2012. Only 27% of southern senators are Democrats, while 62% of Union state senators are Democrats. And 29% of southern members in the House are Democrats compared to 54% in states or territories that were part of the Union.

Thus, it seems to me that minorities have a pretty good idea of what they are doing when joining the Democratic party. They recognize that the Democratic party of today looks and sounds a lot more like the Democratic party of the North that with near unity passed the Civil Rights Bill of 1964 than the southern Democrats of the era who blocked it, and today would, like Strom Thurmond, likely be Republicans.

© Guardian News and Media 2013

[1962 photo of Barry Goldwater via Wikipedia.com]