WASHINGTON (MarketWatch) - The Federal Reserve's decision Wednesday to buy $300 billion in longer-term Treasury securities has ignited a firestorm, with analysts saying it will either cause a currency crisis or jolt the economy out of the morgue.

"We're in a car heading for a cliff and the Fed has just stepped on the gas," said Peter Schiff, the author of a best-selling book 'Crash-proof' and one of a handful of economists who worried about the economy long before it slipped into a severe recession.

“ 'We're in a car heading for a cliff and the Fed has just stepped on the gas.' ” — Peter Schiff, economist

On the other hand, David Jones, chief executive of DMJ Advisors and a long-time Fed watcher, hailed Bernanke's decision as a "turning point" for the economy.

The Fed's plan now is essentially to print money to raise the supply of credit. It wants to push investors out of Treasurys into riskier assets, but investors might balk, said Ian Shepherdson, economist at High Frequency Economics.

"It is a step in the dark. We simply do not know how this will play out because there is no prior experience to use as a road map," Shepherdson said.

Schiff believes that the move will lead to a collapse of the value of the dollar, an outcome he has long predicted.

"Bernanke has sent a giant sell signal to the rest of the world to sell their Treasurys to the Fed. There is going to be a stampede," Schiff said.

"This is going to be a currency crisis. That's what is coming," he added.

Schiff believes that the recession was the "cure" for an economy built on the sands of consumer debt.

Many analysts believe Fed chief Ben Bernanke decided to take the unprecedented step because Congress and the Obama administration now seemed paralyzed as public outrage builds over bailouts for Wall Street and bonuses paid to employees of American International Group.

Bernanke has said repeatedly in the past month that the economy can not recover unless the financial sector is willing to lend.

Some economists were pragmatic about the move, saying that if it worked, it might be worth it.

Many just don't think it will work.

Lou Crandall, economist at Wrightson ICAP, said he doesn't think yields will stay low.

"Once the initial surprise wears off, the market tends to look past public-relations moves in most cases. Ultimately, we think the market is likely to focus on the fact that the net market supply of intermediate- and long-term Treasuries is still growing rapidly even after taking the Fed's buybacks into account," he said.