"I used to think that if there was reincarnation, I wanted to come back as the President or the Pope or as a 400 baseball hitter. But now I would like to come back as the bond market. You can intimidate everybody."

They were the famous words of James Carville who served as Bill Clinton's Chief Strategist.

The meaning was clear.

Nobody can take on the bond market and that includes the US President.

We can't be entirely sure why Donald Trump has U-turned on tariffs and suddenly announced a 90-day pause.

But this latest unexpected twist comes on the same day as the chaos in the stock market spilled over into the bond market.

While Mr Trump could ignore the falling shares on the New York Stock Exchange for a few days, once US Treasuries or bonds began to drop the self-imposed financial crisis went into a different league.

This is because it resulted in the cost of borrowing for America going up quickly.

The US national debt is enormous.

So an extended period of rising interest rates on the bond market would mean the cost of servicing those borrowings would escalate rapidly.

It would feed through to consumer loans and mortgages rapidly.

It was too large a risk for any administration to take.

China is one of the largest holders of US government bonds and there has been speculation it may have been selling treasuries on the market to pressurise the Trump administration.

But the battle with China is far from over because Washington has increased tariffs on its goods to 125%.

For other countries the pause will be a welcome reprieve after the madness of recent days.