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Using sudo with an alias

Typically sudo will ignore any aliased commands from your .bashrc, .bash_aliases, or the alias command. For example, I use "ll" as an alias for "ls -lh". Typing "ll" will give me a long-listing of a directory's contents, while typing "sudo ll" will give me:

sudo: ll: command not found

I learned this when I tried to create an alias for "shutdown" that would refuse to shutdown if rtorrent was running. Unfortunately you need root privileges to use /sbin/shutdown, and sudo would completely ignore the clever script I aliased as "shutdown". The solution is an additional alias:

alias sudo='sudo '

The space following "sudo" tells bash to check if the command that follows the space is also an alias. From the bash man page:

man bash

...
If the last character of the alias value is a blank, then the next command word following the alias is also checked for alias expansion.
...

Now my aliased shutdown script is called even though it's being run with sudo. I've heard of another solution (also an alias), but I haven't tried it (1) because this one works just fine, and (2) because I don't understand why it works (if it does work). Here it is:

alias sudo='A=`alias` sudo  '

I'm not sure if it's just the hard way of doing things, or if it's somehow better, worse, or different.

Here's a copy of my current .bash_aliases file. This is a fresh install, so I'll probably add a lot to it in the future.

# Shortcuts
alias ll='ls -lh'
alias la='ls -lhA'
alias l='ls'
alias c='clear'
alias x='exit'
alias q='exit'

# Don't run shutdown if rtorrent is running - as long as there's a screen with "tor" in its name, shutdown won't run (unless you call /sbin/shutdown, or unalias it)
alias shutdown='/home/james/scripts/safe.shutdown.sh'

# When using sudo, use alias expansion (otherwise sudo ignores your aliases)
alias sudo='sudo '