UPDATED 4 SEPTEMBER 2013
Below we use Optimal Classification (OC) in R to examine the ideological positions of members of the House who signed letters from Rep. Barbara Lee (D-CA) or Rep. Scott Rigell (R-VA) calling for Congressional vote on authorization for the use of military force in Syria. 58 Democrats signed the Lee letter and 116 members (98 Republicans and 18 Democrats) signed the Rigell letter.
Though both letters stopped short of opposing US air strikes in Syria, we think they are useful tea leaves in discerning likely ideological patterns on the authorization vote after Congress reconvenes (currently scheduled for September 9). The Lee letter seems especially dubious about using military force in Syria, especially without multilateral support.
The ideological split between MCs who signed and did not sign the Lee letter is far cleaner than for the Rigell letter. The 58 signatories to the Lee letter are among the most liberal members of the House as measured by their first dimension score (their mean first dimension score is -0.78 compared to 0.12 for those who did not sign the Lee letter). So, at least among congressional Democrats, voting on the authorization of force resolution may fit the traditional left-right divide with the most liberal Democrats opposing the resolution and more moderate Democrats supporting it. House Minority Leader Nancy Pelosi (D-CA) has been a vocal supporter of the use of military force in Syria but has also said she will not whip caucus members on the vote. But there are 127 House Democrats to her right (she has a first dimension score of -0.75), and so Democrats could split in favor of the resolution by a wide margin.
It is more difficult to discern ideological patterns between House Republicans on the Rigell letter. The divide here seems to be better modeled with the second dimension (which we have previously suggested could represent an “establishment vs. outsider” cleavage), but the split here is very muddled.
We will be updating this post as more members of Congress announce their positions on the authorization of force in Syria resolution.
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UPDATE (4 SEPTEMBER 2013): Using the Washington Post’s excellent whip count of where MCS stand on the Syria authorization of force resolution, below we plot the announced Yeas and Nays in the Senate and House. We combine the Strong and Lean Nays, and in the right panel in each plot show the undecided/unannounced members in purple.
In the Senate, there appears to be a fairly strong ideological divide among Republicans, with the most conservative Republicans opposing military intervention and the more moderate Republicans supporting the resolution. If the predicted divide holds for the remaining Republicans, the spatial model predicts a narrow 21-25 split among Senate Republicans against the Syria resolution. There is very little ideological difference between Democrats in the 113th Senate and so we wouldn’t expect a clean ideological split here (interestingly, the Senate Democratic Caucus’s most liberal member — Sen. Bernie Sanders (I-VT) — and its most conservative — Sen. Joe Manchin (D-WV) — are both Strong or Lean Nays on the Syria resolution.
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In the House, there is a wider range of members across the ideological spectrum who oppose the use of military force in Syria. When grouping the Lean and Strong Nays together as we did in the Senate, this totals 142 MCs as opposed to 14 MCs who are announced Yeas. 56 MCs are Strong Nays, and we isolate these members in the second plot below. Both groups, though, are very ideologically diverse. For instance, very liberal Rep. Keith Ellison (D-MN) and very conservative Rep. Eric Cantor (R-VA) both support the Syria resolution. House Democrats who are Lean or Strong Nays are a bit more liberal than the Yea/unnanounced House Democrats, but only by a small margin (a mean first dimension score of -0.73 versus -0.67; only strong Nays have a mean of -0.72). Both groups of House Republicans are virtually ideologically indistinguishable (mean of 0.60 versus 0.59). Consequently, the cutting line runs horizontally and splits MCs along the second dimension, although it is quite possible that this is simply fitting noise. We will continue to update these plots as new positions are announced.
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