Well, what you have so far, is all that background stuff I posted earlier, detailing Arnor's long struggle against Angmar, which has recently been heating up again.
In that background, you have been trying to work out their strategy; you know that the Ruling Council is split into Offensive Hawks and Defensive Doves. You know that the recently destroyed fortress of Emblyosse wass meant to be the lynchpin of a defensive strategy, but at the same time, they just poured a load of troops into Cardolan to help garrison Baranar, which would seem odd on a purely defensive strategy, to stretch yourself so.
Then, you have the prophecy of Malbeth the Seer- that Arvedui will be the last King of Arthedain, and so that Arthedain itself will not survive his rule.
Baranar was actually an essential part of his plan, so understand that and you will understand the lot.