While updating, via a comment, my post about the incumbent Vice President of Panama who had become opposition leader and has now been elected President, I got to probing some of the biographical data.
I cite some data there about the propensity of vice presidents to become president, and of presidents (whether previously VP or not) to change parties prior to making it to the top job. I noted that presidents are significantly more likely to have changed parties at some point than are prime ministers in parliamentary systems: 40.7% vs. 24.6%.* This is, of course, totally consistent with the theory of “presidentialized” parties, whereby party loyalty is less important than electability when assessing candidates for the top job.
I wondered about premiers in the two sub-types of semi-presidential system.
We have data on the career-long party affiliations of 105 premiers in premier-presidential systems and 134 premiers in president-parliamentary systems. The basic distinction by subtype is in whether the formal accountability of the premier is exclusively to the legislative majority (premier-presidential) or dually to the legislature and president (president-parliamentary).
35.1% of premier-presidential premiers had switched parties before ascending to the post, whereas only 17.1% of their counterparts in the other subtype had. That is significant at p=.002.
The effect is in the direction that I expected but bigger than I expected. I figured that where the presidency is the more dominant constitutional actor, i.e. in the president-parliamentary systems, presidents would tend to appoint loyalists, who in turn are less likely to have switched parties at some point.
However, that more than a third of premiers in premier-presidential systems have switched strikes me as high. This is, allegedly, the more “parliamentary” of the two subtypes. On the other hand, that they come down right between the top executives in the two pure types makes sense. In fact, the differences between premier-presidential premiers and either parliamentary PMs or elected presidents (of any regime type) are not significant.
Thus, at least in terms of their tendency to have party-switched, premiers in premier-presidential systems mirror the genuine hybridity of their regime type, whereas their counterparts in president-parliamentary systems look like the ultimate in loyalists. That seems about right!
* That’s presidents of pure presidential systems; if we include semi-presidential presidents, it hardly changes: 41.6%. In some respects, presidents are presidents, regardless of other regime features.