The question is: why is the US backing out of this treaty now when they knew Russia had been violating it for years. I believe the US is preparing for a new arms race with China and is just lining up the paperwork.

The massive arms race in the 70s & 80s is what arguable took down the Soviet Union by applying too much pressure to a shaky economic system. With major cracks showing in the Chinese economy, is the US beginning to employ this tactic again?

Edit: I added this comment before reading the article based on news stories I heard yesterday. The article is basically positing the same theory.