Is it possible for a new, third political party to succeed in the american political system? what can third parties hope to attain?

It was possible earlier on. I don't think so now. I had hoped for the Libertarians, but they cannot seem to really gain traction. I live in Canada where we have 5 different parties. I like to report that one of them is totally dedicated to splitting Canada up. We in the west won't vote for such a thing (it is a party centered in Quebec), but we might push for a conservative candidate who would advocate the dissolution of Canada. We were pretty angry with the east for awhile. Then oil prices fell, and with that decline came the decline of the power in the west. I live in Alberta.

I watch with dismay what is happening in the United States. The Dems and Reps are really the same party and neither has an apparent will. Both are dominated by an unseen force that has greed as its underlying motive. 

Neither has any answer for the deficit which grows at speeds that are not to be understood. The federal debt alone would take 60000 from every man woman and child to pay off. then there's the state and municipal debts which no one is talking about until a Detroit event happens.

What can a third party do? The early 90s was the time for a third party before the dot com bubble and the housing bubble in 2007-8. Ron Paul (Texas) gave it his best shot. He was the last hope of reform. Nobody was listening. Nobody was really home. 

My answer is no a third party cannot succeed. There is little hope. And they (a third party other than Ron Paul) have nothing much to offer.