Unclear about verbose regex syntax (excaping whitespace)

[Roy Smith]

The docs for re.VERBOSE say, "Whitespace within the pattern is ignored, except when [...] preceded by an unescaped backslash".  It's unclear exactly what that means.  If my pattern is:

<backslash><space><space>

is the second space considered to be preceded by a backslash, and thus taken literally, or does the backslash only apply to the first <space>?  I suspect the latter, but it's somewhat ambiguous.