A special place in hell for who?

European Council president Donald Tusk has been getting a lot of stick from Brexiteers recently for this comment:

I've been wondering what that special place in hell looks like, for those who promoted #Brexit, without even a sketch of a plan how to carry it out safely.

— Donald Tusk (@eucopresident) February 6, 2019

Some on the Leave side have reacted angrily. Some on the Remain side have taken this reaction as a sign that they had no plan to begin with. For example:

He was only talking about the ones with no plan. Why are they all taking it so personally?

— James O'Brien (@mrjamesob) February 6, 2019

James O'Brien is right about many things, but I don't think he's right about this. The crucial question is whether Tusk is describing all Brexit-promoters as having no plan (which is how I read it), or pointing only to those Brexit-promoters who had no plan (which is how James O'Brien read it). That's a linguistic question, and it has to do with how the prepositional phrase (PP) "without even a sketch of a plan how to carry it out safely" is to be interpreted.

PPs within noun phrases can be interpreted in two different ways, just like relative clauses. They can be either restrictive or non-restrictive. Restrictive PPs pick out a particular subset of the people (or things) described by the unmodified noun phrase. Non-restrictive PPs add extra information about the people described by the unmodified noun phrase. Compare the following examples:

1. The Brexiteers, who had no plan, are going to hell. (non-restrictive)
2. The Brexiteers who had no plan are going to hell. (restrictive)
3. The Brexiteers, with no plan, are going to hell. (non-restrictive)
4. The Brexiteers with no plan are going to hell. (restrictive)

The first two examples involve relative clauses, and the last two involve PPs. In both cases it's the commas that make all the difference, at least if your intuitions are anything like mine. In the restrictive (2) and (4), only those Brexiteers who didn't have a plan are going to hell. In the non-restrictive (1) and (3), on the other hand, all the Brexiteers are going to hell, and in addition they're all described as not having a plan.

Looking again at Tusk's tweet, he used a comma, which suggests to me that the intended reading was the non-restrictive one. We can't be sure that was what he intended, of course: punctuation is one indicator, but it's not a particularly reliable guide to anything, especially on Twitter. But in the video version there's a pause, which also suggests a non-restrictive interpretation.

What's particularly interesting is that Tusk didn't actually assert that all Brexiteers had no plan, even under the non-restrictive reading. Non-restrictive modification is tricky like that: the information introduced by the non-restrictive phrase is backgrounded, which is one of the things that makes them particularly annoying to argue against.

Anyway, it's pretty clear that the point is mainly an academic one, since no one actually did have a plan for Brexit, either on the Leave or the Remain side (unless you count the weirdos and supervillains who were gunning for a no-deal Brexit all along; and even that arguably counts as not having a plan how to carry it out safely). But the broader point is that syntax and semantics are interesting! And hopefully I'll see you in that special place in hell that's reserved for people who turn serious political issues into fun linguistics problems. :)