Quotes from Stephen G. Breyer

The complexity of modern federal criminal law, codified in several thousand sections of the United States Code and the virtually infinite variety of factual circumstances that might trigger an investigation into a possible violation of the law, make it difficult for anyone to know, in advance, just what particular set of statements might later appear (to a prosecutor) to be relevant to some such investigation.

In this country, amid the clash of arms, the laws are not silent. They may be changed, but they speak the same language in war as in peace. It has always been one of the pillars of freedom, one of the principles of liberty for which…we are now fighting, that the judges…stand between the subject and any attempted encroachments on his liberty by the executive, alert to see that any coercive action is prohibited in law.100

As we have seen, despite holdings by the European Court of Justice that EU law trumps member-state law, many national courts have insisted on retaining the final word as to whether a rule of European law conforms to their own constitutional requirements. And if this is so among nations committed to a measure of political and economic union, how much less likely is foreign law to impinge upon the sovereignty of one not so encumbered?

Ironically, the only two "relevan[t]" metrics that the Court does identify are "how and why" a gun control regulation "burden[s the] right to armed self-defense." In other words, the Court believes that the most relevant metrics of comparison are a regulation's means (how) and ends (why)—even as it rejects the utility of means-end scrutiny.