From the essay:

"Finally, I’ll add a different kind of example, an example we mentioned in an earlier essay: it is worth noting that during the debate over the Brexit treaty, from 2016-2020, the Tories in the House Of Lords were far more reasonable and rational than the Tories in the House Of Commons. This example is especially interesting since we are comparing people who belonged to the same political party. The only difference between them is that one group was free to think about the long-term consequences of the treaty, while the other group was under pressure to pander."