Federal Reserve Chairman Jerome Powell said Wednesday the central bank would fight the next economic downturn by buying large amounts of government debt to drive down long-term interest rates, a strategy that has been dubbed quantitative easing, or QE.

In testimony before the Senate Banking Committee, Powell said the Fed had two recession-fighting tools; buying government bonds, known as QE, and communicating clearly with markets about interest-rate policy, routinely considered as “forward guidance.”

“We will use those tools — I believe we will use them aggressively should the need arise to do so,” Powell said.

The Fed has traditionally been able to slash interest rates to fight a recession often by as much as 5 percentage points. But that’s impossible now because the Fed’s benchmark rate is currently in a range of 1.5%-1.75%.

“We will have less room to cut,” Powell said.

As a result, once the Fed trims rates close to zero, if it does, “it is much more likely we will have to turn to the tools we used in the financial crisis,” namely asset purchases and forward guidance, Powell said.

Some economists worry that these tools will not pack much punch in the next downturn. They note that the yield on the 10-year Treasury note TMUBMUSD10Y, 0.701% is already low, at 1.634% currently, and can’t fall much further.

Powell has dismissed the notion that the Fed would push its benchmark rate into negative territory.

Negative interest rates have been a favorite talking point of President Donald Trump, who has regularly called on the Fed to take the step.

Other countries like Switzerland and Germany have been using the negative rate tool.

Powell told lawmakers that Congressional spending plans aim to support the economy if it weakens.

He urged them to put the federal budget on a more sustainable path while the economy is strong.

The U.S. national debt is currently $23 trillion.

Asked what level would be concerning, Powell replied: “I would be concerned now.”

The Congressional Budget Office forecast that the national debt would top $31 trillion by 2030, the highest level since World War II.