Bingo !
They would not need a huge military force of massive fleet of ships to invade the West Coast.
All they need is to get the US bogged down in a major war somewhere else half way around the world, like the middle east.
Then threaten to dump US’s holdings ( or actually dump USA’s debt ) of debt to sink the economy and cause chaos and massive shortages.
Iran shuts of the Straight of Hormoz that sends oil to $ 200 a barrle or more since the US domestic fracking industry is reling, therefore cause massive shortages of oil and gasoline here in the US.
Once that is accomplished they send a few EMPs to take out the west coast’s electrical infrastructure once the chaos has reached it’s peak.
It is plausible.
The Jade Helm exsersises will keep what ever refugees from leaving the west coast going into the interior of the US.