Darn HTML. Amended below:

That said, let me offer a case where I might deviate from the norm of using a single space. Periods within a sentences can be hard to read, e.g. "I live in the U.S._Marshall Islands is full of angry ants!" In this case, "I live in the U.S.__Marshall Islands is full of ants!" is clearer.

I have also been taught all my life to use two spaces after a period (full-stop). But like many things taught in high-school, the two-space doctrine was prescriptive knowledge imparted authoratively. It was full of the "what" but devoid of the "why" like much of everything else I learnt in high school.

I dislike dogma but a reaction that is itself dogmatic is no remedy. The rule isn't important. The reasoning behind the rule is what matters. It seems fair to say that there was a reasonable purpose for two-spaces in the past. It boils down to legibility. Without two-spaces after a period, typewritten, monospace sentences looked uncomfortably squished together. Porportional fonts and modern word-processors have addressed this problem, though not necessarily other use-cases of periods within a sentence.

That said, let me offer a case where I might deviate from the norm of using a single space. Periods within a sentences can be hard to read, e.g. "I live in the U.S. Marshall Islands is full of angry ants!" In this case, "I live in the U.S. Marshall Islands is full of ants!" is clearer.

So, as to whether it is wrong to use two spaces after a period ending sentence, i would say that isn't wrong. It is simply not particularly useful as a general practice. My own objections to the two-space-or-die rule has less to do with whether or not there is a One True Way. It is that we cling to these practices because the Practice itself has become the Thing. Arguing that it is right because we have been taught that way panders to uncritical thinking. Let's return to reason before practice.

Regards,
EK