Does Git really need a commit message to go with a commit?

git-commit(1) doesn't allow you to make a commit without a commit
message. This is annoying and doesn't properly preserve history in
applications like snerp-vortex which replay a SVN dump into Git. You
have to add `$msg = "Git made me do it" unless length $msg' somewhere.

Is there really no way to add a commit with no message with the git
tools? Will anything break if I manually construct a commit with no
message? Are commit messages inherently part of the format or does
git-commit(1) just think it knows better than me?