but in general Libras aren't the toughest signs in the zodiac
True, Libras tend to be lovers more than fighters...but I attribute that more to their indecisiveness than to their inability to defend themselves; it's hard to fight when you see both sides - who do you fight??? And, of course, they have to stop to consider if each swing is fair! (If you want someone to make a fast and concrete decision, don't ask a Libra! LOL) No, Libras would rather reason (verbal) than rumble (physical) - or so, that's my experience!
I love Libras - I have a very strong Libra rising.