Yeah this is the safe bet. The mechanism of warlordization will be the state governments - as the federal government recedes into only maintaining the military and printing the currency, state governments will fill the void and there will be a moment where the Governors of the big states will all have more domestic power than the President. I could see one of them declaring themselves independent and it going about as well as Catalonia's attempt did, leading to the rest to realize that that's not in the cards.