Even though it’s now back under government control, the jihadist takeover of the border town of Arsal was the most serious spillover from Syria into Lebanon yet. There have been other encroachments, but this was by far the most significant. The fact that it one seemed to be led by IS fighters made it all the more worrying. Although, contrary to some speculation, it doesn't mean that IS is looking to mount a full invasion into Lebanon, as some analysts speculated.