Why do I require an "elif" statement here?

[Jim]

Could somebody tell me why I need the "elif char == '\n'" in the
following code?
This is required in order the pick up lines with just spaces in them.
Why doesn't
the "else:" statement pick this up?

OLD_INDENT = 5  # spaces
NEW_INDENT = 4  # spaces

print 'Reindent.py:'
print '\nFrom file %s' % infile
print 'Change %i space indentation to %i space indentation.' % (
                                         OLD_INDENT, NEW_INDENT)
print 'And place revised file into %s' % outfile

whitespace = ' '
n = 0
nline = 0

for line in input.readlines():
    nline += 1
    # Only look at lines that start with a space.
    if line[0] == whitespace:
        i = 0
        for char in line:
            i += 1
            if char == whitespace:
                pass
            elif char == '\n':          # Why do I need this for a
blank line with only spaces?
                output.write(line)
                break
            else:                        # Why doesn't the blank line
get picked up here?
                x = line.count(whitespace*OLD_INDENT,0,i)
                # Reindent lines that have exactly a multiple of
OLD_INDENT.
                if x > 0 and (i-1)%OLD_INDENT == 0:
                    output.write(whitespace*NEW_INDENT*x+line.lstrip())
                    n += 1
                    break
                else:
                    output.write(line)
                    break
    else:
        output.write(line)

input.close()
output.close()
print 'Total number of %i lines reindented out of %i lines.' % (n,
nline)