Will the House of Representatives support US military action against Syria?
This chart suggests that a Yes vote will prove difficult:
The scatterplot is from the voteview blog. Members of Congress are labelled either D (Northern Democrat), S (Southern Democrat; a now rare breed that is included so that analysts can make historical comparisons) or R (Republican). Those who have said they will support the motion are in red; those that have said they will oppose it or who “lean nay”, according to the Washington Post, are in blue.
The horizontal axis labelled “First Dimension” plots each member by their position on an ideological spectrum from “liberal” on the left to “conservative” on the right. This is a standard measure often cited in the political science literature, and one which Nate Silver explains in this post. As you can see from the above graphic, Republicans are in the right half and the Democrats are all in the left half.
The First Dimension spectrum forms the basis for popular charts which show how Congress has become more polarised over time.
The vertical axis labelled “Second Dimension” is where things get a bit more interesting. It plots each member on a different spectrum, this time from what researchers call “establishment” at the top to “outsider” at the bottom. Tea Party Republicans can often be found in the bottom right of charts which combine the two dimensions.
The political scientists behind the voteview blog have found that this dimension is increasingly useful in explaining votes in the House, especially on issues such as data surveillance. In these cases, libertarians and liberals are often found on the same side; whereas on a vote to increase spending on welfare, say, they might not be.
Crudely put, when issues of executive power have arisen, where a member of the House is on the establishment vs outsider axis might be as useful in predicting their vote as where they are on a left vs right axis.
All of which brings us to Syria. Here is a similar chart but this time for the Senate:
The important thing to note is the gradient of what the researchers call the “cutting line”. If it is vertical, such as in the case above, the line suggests that the traditional ideological division can explain the direction of votes. As can be seen from the cluster of “Nay” votes to the right of the line, Senators who have said they will oppose (or where the Post counts them as leaning No) authorisation are mostly from the conservative wing of the party.
In contrast, the cutting line in the House chart is almost horizontal. This suggests that the No voters transcend the traditional left vs right (or liberal vs conservative) divide. “Both [yes and no votes] … are very ideologically diverse”, say the researchers in the voteview post. Instead, it seems like the establishment vs outsider dimension might be more useful.
Caveat time: the politicians might change their minds, the Post might have its count wrong, there might be a lot of noise in the sample, and it is only a model, after all.
Caveats mentioned, it is time to add some magenta to the palate.
In the charts below, voteview has added the reportedly undecided Senators and Congressmen based (I think) on positions stemming from previous votes. Their points are in a lurid magenta colour. The cutting lines remain in the same place. As should be clear, the House looks like it might be tricky to win over.
Reports this morning suggest that Mr Obama would lose a House vote if it were held today. Ed Luce, the FT’s US columnist, writes that he “would put the chances of a House yes at 50:50 or below”. Playbook, the influential Washington briefing from Politico, agrees.
On both sides of the Atlantic, the debate on Syria suggests that there are gaps between the public and the foreign policy (rather than the defence) establishment, and between the legislative and executive branches of government.
In the UK, the House of Commons vote to reject action revealed these gaps through a baroque display of incompetence. In the US, the House of Representatives could be set to affirm these divisions. And given that the House is inherently more attuned to US public opinion, it might show us something about American society, too. That is unless Mr Obama can persuade Congress otherwise.