Societe Generales strategist Albert Edwards warns that the Federal Reserve’s penchant for pouring more and more liquidity into the U.S. financial machine will eventually lead to a “deflationary bust” and force the central bank to turn to negative interest rates in a recovery effort.

“Once politicians have their hands on this policy tool, make no mistake, they will never ever hand it back to the Central Banks.”

Edwards blasted the Fed’s monetary decisions in his latest note to clients, calling it a “new level of fiscal debauchery for the U.S.” that won’t stop as the central bank tries to maintain a record-long economic expansion that continues to crawl along at a snails pace.

And when the crash comes, Edwards predicts the only thing the Fed will be able to do is engage in negative interest rate policy (NIRP).

“(I’m) now more convinced than ever before that the coming deflationary bust will take the US 30-year yield below zero,” he said. “I am also convinced that helicopter money will be the chosen way out of this deflationary quagmire, especially as it becomes increasingly clear that there is now no way left to reverse every government’s exploding fiscal liabilities. The Ice Age is nearing the end.”

Looking around the world, negative interest rates are now the norm in Japan and parts of Europe. Around $11 billion of global sovereign debt is yielding in the negative currently, and U.S. President Donald Trump has blasted the Fed in the past for not being more open to trying NIRP.

Edwards also thinks Modern Monetary Theory (MMT), aka “helicopter money” is inevitable as well, which backers of the policy believe is OK to use as long as inflation doesn’t balloon out of control.

“You can call it Modern Monetary Theory (MMT), you can call it ‘Fiscal and Monetary Co-operation,’ or you can call it whatever you like, but there is only one realistic way out of this mess — and that is for governments to inflate away their debts,” Edwards said in his note.

“Does anyone seriously believe that any democratically-elected government would be willing to raise taxes or cut government spending and future pension/health benefits in a bid to delay the fiscal timebomb? Of course they wouldn’t! And any government that attempts to do so will be hounded from office by an indignant public armed with pitchforks and much else besides.”

Fed Chair Jerome Powell told Congress in a November meeting that negative interest rates “would certainly not be appropriate in the current environment” of economic expansion.

And as far as direct money injections through MMT? The Fed is already participating in a form of quantitative easing in the repo markets, and Edwards thinks government officials won’t be able to resist the power a tool like MMT could provide.

“Helicopter money will work for Joe Sixpack much more effectively than it will for Mike Moneybags — and so it will be much more widely popular,” Edwards said. “Once politicians have their hands on this policy tool, make no mistake, they will never ever hand it back to the Central Banks.”