Mootaz,
If Kaddaffy did invade Tunisia after Ben Ali departed, Tunisian would have joined rank with him...Just like they are doing now with the Lybian after his death. But there is two things that you ignore...The first, because you don't know your country well (that is if you are Tunisian) that Bourguiba has formed , during his reign, a political elite that will always fight to keep what Tunisia has gain in freedom and in freedom of thought ...And you can see that now in the street of Tunisian from the men to the women that are standing against the islamists nahdha and salafist included...
Second, your neighbor to the west, will never let kaddaffy troops put one foot in Tunisia...that was made clear to him in the 80's...and thru the 90's