The 2015 Texas Senate, from left to right

Photo by Rick Mach

Political scientists have long used roll call votes cast by members of Congress to plot them on the Liberal-Conservative dimension along which most legislative politics now takes place. This ranking of the Texas Senate uses all 1,491 non-lopsided roll call votes taken during the 2015 regular session to accomplish a similar task. As with past rankings, this uses a Bayesian estimation procedure developed by Stanford University professor Simon Jackman.


In the figure below, Republicans are indicated by red dots and Democrats by blue dots. The figure is based on the roll call vote analysis, and for each senator provides a mean ideal point, referred to as the Lib-Con Score, along with the 95 percent credible interval (CI) for this point estimate. If two senators’ CIs overlap, their positions on the ideological spectrum might be statistically equivalent, even if their Lib-Con Scores are different. Also included are vertical dashed black lines to indicate the location of the respective median Democratic (D) and Republican (R) senator. (Find a table with the 31 senators ranked from most liberal (1) to most conservative (31) here.)

As with their House counterparts, it’s important to keep in mind that Republican senators can register Lib-Con Scores that are noticeably lower than those of most of their fellow Republicans while remaining conservative. It simply means they have voting records that are less conservative than most of their Republican colleagues. The same is true for Democrats at the other end of the rankings. For 2015, every Republican senator’s Lib-Con Score is significantly more conservative than that of every Democratic senator; every Democrat’s score is significantly more liberal than every Republican’s.

The Republicans

The 20 GOP senators can be separated into four rough blocs based on their Lib-Con Score relative to those of their fellow Republicans. At the conservative edge of the ideological spectrum are four senators whose Lib-Con Scores are significantly more conservative than those of all of their 16 Republican colleagues: Bob Hall of Edgewood, Konni Burton of Colleyville, Van Taylor of Plano and Don Huffines of Dallas. Moving from right to left, the next ideological bloc is by far the largest, containing eight senators, and is anchored by Brian Birdwell of Granbury on one side and Donna Campbell of New Braunfels on the other. The third bloc contains four senators, with Robert Nichols of Jacksonville and Larry Taylor of Friendswood serving as bookends. The final, centrist conservative bloc comprises four senators: Joan Huffman of Houston, Kel Seliger of Amarillo, Craig Estes of Wichita Falls and Kevin Eltife of Tyler. All four of their Lib-Con Scores are significantly more conservative than that of every Democrat, but significantly less conservative than that of every Republican in the other three blocs, with the exception of Taylor in the cases of Huffman, Seliger and Estes.

There was a tremendous amount of new blood in the 20-member Republican caucus this session, with eight freshmen and four sophomores. Several of the freshmen replaced a senator who in 2013 was either located in the centrist conservative wing of the Republican delegation (Brandon Creighton of Conroe, who replaced Tommy Williams; Hall, who replaced Bob Deuell; Huffines, who replaced John Carona; and Charles Perry of Lubbock, who replaced Robert Duncan) or was a Democrat (Burton, who replaced Wendy Davis). Freshmen accounted for eight of the 10 most conservative senators in 2015, and sophomores for three of the 12 most conservative. In all, 11 of the 12 most conservative senators in 2015 were elected between 2012 and 2014 (the 12th was elected in 2010). In contrast, among the eight senators in the two least conservative Republican blocs in 2015, there is only one sophomore (Taylor), with the next two most junior senators having been elected in 2008 (Huffman) and 2006 (Nichols), before the rise of the Tea Party movement in Texas.

The ideological wave that swept through the Senate Republican caucus, with centrist conservative and conservative senators being replaced by even more conservative senators, resulted in several veteran senators — who as recently as 2013 and 2011 were located to the right of the party median — moving to the left of the party median in 2015 (Nichols, Jane Nelson of Flower Mound and Troy Fraser of Horseshoe Bay). This new location is not the product of a change in the core ideological beliefs and values of these senators, but rather the consequence of the election of a host of Republican senators whose floor voting behavior is even more conservative than that of these more senior lawmakers. Fraser, Nelson and Nichols remained very conservative in 2015; it’s just that their eight new GOP colleagues were substantially more conservative in most cases than the senators they replaced.

The Democrats

The 11-member Democratic senate delegation split into three blocs in 2015. At the liberal edge of the ideological spectrum is a group of five senators, ranging from the Senate’s most liberal member, Rodney Ellis of Houston, to José Menéndez of San Antonio. The CIs for these five senators overlap, meaning the Lib-Con Score of any one of them is not significantly more or less liberal than that of any of the other four. For instance, since Menéndez’s CI overlaps with Ellis’, it can’t be concluded that Menéndez is significantly less liberal than Ellis or that Ellis is significantly more liberal than Menéndez.

The next bloc of Democratic senators, five total, runs from the median Democrat, Judith Zaffirini of Laredo, to Juan “Chuy” Hinojosa of McAllen. With the exception of Zaffirini (whose CI overlaps with that of Menéndez), the five each have a Lib-Con Score that is significantly less liberal than that of all of the members of the most liberal Democratic bloc and, with the exception of Hinojosa, have a Lib-Con Score that is significantly more liberal than that of the sole member of the party's conservative wing in 2015, Eddie Lucio Jr. of Brownsville. 

Two rebels with a centrist cause

If Eltife was the ideological rebel of the 2015 GOP delegation, with a Lib-Con Score significantly less conservative than that all but three of his 19 fellow Republicans, then Lucio was his mirror image within the Democratic caucus, with a Lib-Con Score significantly more conservative than that of all but one of his 10 fellow Democrats. For those in Texas who long for the days of more ideological proximity, and even overlap, among Democrats and Republicans in the Texas Senate, Eltife and Lucio represent the most visible vestiges of this fading past. With Eltife’s decision not to run for re-election in 2016, the ideological gulf separating Democrats and Republicans in the Senate is likely to be even wider in 2017.

Disclosure: Rice University is a corporate sponsor of The Texas Tribune. A complete list of Tribune donors and sponsors can be viewed here.

Mark P. Jones

Fellow in political science at Rice University’s Baker Institute