You need to prove you can actually be a part of a real coalition that can win elections. What I've seen of libertarians is that they want all on their agenda, and will go home with the their ball if they don't get it.
Our system doesn't work with coalitions, that's a parliamentary thing. Our system is all or nothing, and it's obvious by looking at our ballooning and intrusive federal government that working within the Republican party to make it more governmentally conservative isn't effective.
Let's just hope that this election will serve as a wake-up call to the Republican party. Maybe the libertarians will now be a special interest group that the Republicans will change their actions for in order to get reelected.
Personally, I'm just glad there were no worthwhile libertarians on my ballot for federal positions, so I didn't have the hard choice.